Dialog 使用详解

Posted 2022-06-15 wangjie1990

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本篇文章主要介绍 Android 开发中的部分知识点，通过阅读本篇文章，您将收获以下内容:

1. 简单对话框
2. 多选按钮对话框
3. 单选按钮对话框
4. 列表对话框
5. 水平进度条对话框
6. 圆形进度条对话框
7. 自定义图文对话框
8. 自定义输入对话框
9. 自定义样式对话框
10. 自定义Loading样式对话框
11. 继承 DialogFragment 实现对话框
12. Activity形式的 对话框
13. 倒计时 30s Dialog实现

Dialog 是Android 常用控件之一，主要以弹出框的形式与用户进行交互。对话框是提示用户作出决定或输入额外信息的小窗口。 对话框不会填充屏幕，通常用于需要用户采取行动才能继续执行的模式事件。

Dialog 简介

Dialog 继承关系如下：

java.lang.Object
   ?    android.app.Dialog

Dialog 基本样式解析

1.标题

这是可选项，只应在内容区域被详细消息、列表或自定义布局占据时使用。 如需陈述的是一条简单消息或问题（如图 上图中的对话框），则不需要标题。

2.内容区域

它可以显示消息、列表或其他自定义布局。

3.操作按钮

对话框中的操作按钮不应超过三个。

1. 简单对话框

• 实现效果：

• 实现代码如下：

    /**
     * 简单对话框
     */
    public void SimpleDialog(View view) 

        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setIcon(R.drawable.gril).setTitle("简单对话框")
                .setMessage("设置Dialog 显示的内容")
                .setPositiveButton("OK", new DialogInterface.OnClickListener() 

                    @Override
                    public void onClick(DialogInterface dialog, int which) 

                        Toast.makeText(DiaLogMethods.this, "点击了确定按钮",
                                Toast.LENGTH_SHORT).show();
                    
                ).setNegativeButton("Cancle", null).create().show();

    

2. 多选按钮对话框

• 实现效果：

• 实现代码：

/**
     * 多选按钮对话框
     * */
    public void MultiChoiceDialog(View view) 
        final String font[] =  "小号字体", "中号字体", "大号字体", "超大号字体" ;
        final boolean[] MultiChoice = new boolean[]  false, true, false, false ;
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("多选对话框")
                .setIcon(R.drawable.ic_launcher)
                .setMultiChoiceItems(font, MultiChoice,
                        new DialogInterface.OnMultiChoiceClickListener() 
                            @Override
                            public void onClick(DialogInterface dialog,
                                    int which, boolean isChecked) 
                                MultiChoice[which] = isChecked;
                                String choiceString = "";
                                for (int i = 0; i < MultiChoice.length; i++) 
                                    if (MultiChoice[i]) 
                                        choiceString = choiceString + font[i]
                                                + "  ";
                                    
                                

                                if (choiceString.equals("")
                                        || choiceString.length() == 0) 

                                    // 都不选的处理方法

                                    Toast.makeText(DiaLogMethods.this,
                                            "请选择一个内容", Toast.LENGTH_SHORT)
                                            .show();
                                 else 

                                    Toast.makeText(DiaLogMethods.this,
                                            "选择的字体为" + choiceString,
                                            Toast.LENGTH_SHORT).show();

                                

                            
                        ).setPositiveButton("OK", null)
                .setNegativeButton("Cancle", null).create().show();

    

3.单选按钮对话框

• 实现效果：

• 实现代码如下：

    /**
     * 单选按钮对话框实现
     **/
    public void SingleChoiceDialog(View view) 
        final String font[] =  "小号字体", "中号字体", "大号字体", "超大号字体" ;
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("单选对话框")
                .setIcon(R.drawable.ic_launcher)
                .setSingleChoiceItems(font, 0,
                        new DialogInterface.OnClickListener() 
                            @Override
                            public void onClick(DialogInterface dialog,
                                    int which) 
                                Toast.makeText(DiaLogMethods.this,
                                        "选择的字体为:" + font[which],
                                        Toast.LENGTH_SHORT).show();
                                dialog.dismiss();
                            
                        ).setPositiveButton("OK", null)
                .setNegativeButton("Cancle", null).create().show();

    

4. 列表对话框

• 实现效果如下：

• 实现代码如下：

/**
     * 列表对话框实现
     **/
    public void ListItemDialog(View view) 
        final String font[] =  "小号字体", "中号字体", "大号字体", "超大号字体" ;
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setIcon(R.drawable.ic_launcher)
                .setTitle(" 列表对话框")
                .setItems(font, new DialogInterface.OnClickListener() 
                    @Override
                    public void onClick(DialogInterface dialog, int which) 
                        Toast.makeText(DiaLogMethods.this,
                                "选择内容是：" + font[which], Toast.LENGTH_SHORT)
                                .show();
                    
                ).setNegativeButton("Cancle", null)
                .setPositiveButton("OK", null).create().show();

    

5. 水平进度条对话框

• 实现效果如下：

• 实现代码如下：

    /**
     * 水平进度条对话框实现
     **/
    @SuppressWarnings("deprecation")
    public void HorProgressDialog(View view) 

        final ProgressDialog progressDialog = new ProgressDialog(
                DiaLogMethods.this);
        progressDialog.setTitle("进度对话框");
        progressDialog.setIcon(R.drawable.ic_launcher);
        progressDialog.setMessage("加载中...");
        // 水平进度条显示
        progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        // 圆形进度条显示
        // progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        progressDialog.setCancelable(true);
        progressDialog.setButton("Cancle",
                new DialogInterface.OnClickListener() 
                    @Override
                    public void onClick(DialogInterface dialog, int which) 
                        Toast.makeText(DiaLogMethods.this, "取消进度条对话框",
                                Toast.LENGTH_LONG).show();
                        progressDialog.cancel();
                        count = 0;
                    
                );
        progressDialog.setMax(100);
        progressDialog.show();
        count = 0;
        new Thread() 
            @Override
            public void run() 

                while (count <= 100) 
                    progressDialog.setProgress(count++);
                    try 
                        Thread.sleep(50);
                     catch (InterruptedException e) 
                        progressDialog.dismiss();
                        e.printStackTrace();
                    

                
                progressDialog.dismiss();
            
        .start();

    

6. 圆形进度条对话框

• 实现效果如下：

• 实现代码如下：

/**
     * 圆形进度条显示
     **/
    @SuppressWarnings("deprecation")
    public void SpinerProgressDialog(View view) 

        final ProgressDialog progressDialog = new ProgressDialog(
                DiaLogMethods.this);
        progressDialog.setTitle("进度对话框");
        progressDialog.setIcon(R.drawable.ic_launcher);
        progressDialog.setMessage("加载中...");
        // 水平进度条显示
        // progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        // 圆形进度条显示
        progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        progressDialog.setCancelable(true);
        progressDialog.setButton("确定", new DialogInterface.OnClickListener() 
            @Override
            public void onClick(DialogInterface dialog, int which) 
                Toast.makeText(DiaLogMethods.this, "取消进度条对话框",
                        Toast.LENGTH_LONG).show();
                progressDialog.cancel();
                count = 0;
            
        );
        progressDialog.setMax(100);
        progressDialog.show();
        count = 0;
        new Thread() 
            @Override
            public void run() 

                while (count <= 100) 
                    progressDialog.setProgress(count++);
                    try 
                        Thread.sleep(50);
                     catch (InterruptedException e) 
                        progressDialog.dismiss();
                        e.printStackTrace();
                    

                
                progressDialog.dismiss();
            
        .start();

    

注意 ：

水平进度条，圆形进度条的区别 如下：

        // 水平进度条显示
        progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        // 圆形进度条显示
        progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);

7. 自定义图文对话框

• 实现效果如下：

• 实现代码如下：

    /**
     * 自定义图文对话框实现
     **/
    public void CustomImgTvDialog(View view) 

        AlertDialog.Builder builder = new AlertDialog.Builder(this);

        View contextview = getLayoutInflater().inflate(
                R.layout.dialog_custom_img_tv, null);
        LinearLayout linearLayout1 = (LinearLayout) findViewById(R.id.linlout1);
        LinearLayout linearLayout2 = (LinearLayout) findViewById(R.id.linlout2);
        ImageView img1 = (ImageView) contextview.findViewById(R.id.img1);
        TextView tv1 = (TextView) contextview.findViewById(R.id.tv1);
        // 这里可以处理一些点击事件

        builder.setIcon(R.drawable.gril).setTitle("自定义对话框")
                .setView(contextview)
                // 或者在这里处理一些事件
                .setPositiveButton("OK", null)
                .setNegativeButton("Cancle", null).create().show();
    

注意：

1. 自定义图文对话框的布局如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:id="@+id/linlout1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="5dp"
        android:orientation="horizontal" >

        <ImageView
            android:id="@+id/img1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/ic_launcher" />

        <TextView
            android:id="@+id/tv1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:text="this is a test data" />
    </LinearLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_marginBottom="2dp"
        android:layout_marginTop="2dp"
        android:background="@android:color/darker_gray" />

    <LinearLayout
        android:id="@+id/linlout2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="5dp"
        android:orientation="horizontal" >

        <ImageView
            android:id="@+id/img2"
            android:layout_width="wrap_content"
            android:layout_height="45dp"
            android:src="@drawable/gril" />

        <TextView
            android:id="@+id/tv2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:text="this is a test data" />
    </LinearLayout>

</LinearLayout>

8. 自定义输入对话框

• 实现效果如下：

• 实现代码如下：

    /**
     * 自定义EditText对话框
     **/
    public void CustomEditTextDialog(View view) 

        AlertDialog.Builder builder = new AlertDialog.Builder(this,
                android.R.style.Theme_Material_Light_Dialog_Alert);
        View Tittleview = getLayoutInflater().inflate(
                R.layout.dialog_custom_layout, null);
        ImageView img2 = (ImageView) Tittleview.findViewById(R.id.img2);
        TextView textView = (TextView) Tittleview.findViewById(R.id.tv2);

        textView.setText("自定义对话框");
        img2.setImageResource(R.drawable.ic_launcher);
        // 自定义tittle
        builder.setCustomTitle(Tittleview);

        View contentView = getLayoutInflater().inflate(
                R.layout.dialog_custom_et, null);
        EditText username = (EditText) contentView.findViewById(R.id.username);
        EditText passworld = (EditText) contentView
                .findViewById(R.id.passworld);

        builder.setView(contentView);
        builder.setPositiveButton("OK", null).setNegativeButton("Cancle", null)
                .create().show();

    

自定义对话框 布局如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">

    <ImageView
        android:id="@+id/img2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher" />

    <TextView
        android:id="@+id/tv2"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:layout_weight="1"
        android:text="自定义Dialog"
        android:textColor="@android:color/black"
        android:textSize="25sp" />
</LinearLayout>

自定义 EditText内容布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <EditText
        android:id="@+id/username"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="2dp"
        android:background="@drawable/custom_edittext_background"
        android:hint="please input username"
        android:padding="5dp"
        android:textSize="20sp" />

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_marginBottom="2dp"
        android:layout_marginTop="2dp"
        android:background="@android:color/darker_gray" />

    <EditText
        android:id="@+id/passworld"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="2dp"
        android:background="@drawable/custom_edittext_background"
        android:hint="please input password"
        android:padding="5dp"
        android:textSize="20sp" />

</LinearLayout>

9. 自定义样式对话框

• 实现效果如下：

• 实现代码如下：

    /**
     * 自定义样式对话框
     * **/
    public void CustomStyleDialog(View v) 

        // 对话框和activity绑定,所以必须传递activity对象
        Builder builder = new AlertDialog.Builder(this,
                android.R.style.Theme_Material_Light_Dialog_Alert);
        // 获取对话框对象
        final AlertDialog dialog = builder.create();
        // 修改对话框的样式(布局结构)
        View view = View.inflate(this, R.layout.dialog_custom_style, null);

        // 因为在2.3.3版本上,系统默认设置内间距,所以需要去除此内间距
        // dialog.setView(view);
        dialog.setView(view, 0, 0, 0, 0);

        // 找到对话框中所有控件
        Button bt_submit = (Button) view.findViewById(R.id.bt_submit);
        Button bt_cancel = (Button) view.findViewById(R.id.bt_cancel);

        final EditText et_set_psd = (EditText) view
                .findViewById(R.id.et_set_psd);
        final EditText et_confirm_psd = (EditText) view
                .findViewById(R.id.et_confirm_psd);

        bt_submit.setOnClickListener(new OnClickListener() 
            @Override
            public void onClick(View v) 
                // 如果用户没有输入两次密码,告知用户输入密码
                String psd = et_set_psd.getText().toString().trim();
                String confirmPsd = et_confirm_psd.getText().toString().trim();
                if (!TextUtils.isEmpty(psd) && !TextUtils.isEmpty(confirmPsd)) 
                    if (psd.equals(confirmPsd)) 
                        // 当前的对话框隐藏
                        dialog.dismiss();

                     else 
                        Toast.makeText(getApplicationContext(), "两次输入密码不一致",
                                Toast.LENGTH_SHORT).show();
                    
                 else 
                    Toast.makeText(getApplicationContext(), "密码不能为空",
                            Toast.LENGTH_SHORT).show();
                
            
        );

        bt_cancel.setOnClickListener(new OnClickListener() 
            @Override
            public void onClick(View v) 
                dialog.dismiss();
            
        );

        // 展示对话框
        dialog.show();

    

1. 自定义样式dialog_custom_style布局如下：

dialog_custom_style 布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#fff"
    android:orientation="vertical" >

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@android:color/holo_blue_light"
        android:gravity="center"
        android:textColor="@android:color/white"
        android:layout_marginBottom="10dp"
        android:padding="10dp"
        android:text="设置密码"
        android:textSize="20sp" />

    <EditText
        android:id="@+id/et_set_psd"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="2dp"
        android:background="@drawable/custom_edittext_background"
        android:hint="输入密码"
        android:inputType="textPassword"
        android:padding="5dp"
        android:textSize="22sp" />

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_marginBottom="2dp"
        android:layout_marginTop="2dp"
        android:background="@drawable/tittle_bg" />

    <EditText
        android:id="@+id/et_confirm_psd"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="2dp"
        android:background="@drawable/custom_edittext_background"
        android:hint="确认密码"
        android:inputType="textPassword"
        android:padding="5dp"
        android:textSize="22sp" />

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_marginTop="5dp"
        android:background="@drawable/tittle_bg" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="3dp"
        android:layout_marginTop="3dp"
        android:orientation="horizontal" >

        <Button
            android:id="@+id/bt_submit"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_margin="5dp"
            android:layout_weight="1"
            android:background="@drawable/custom_btn_green_selector"
            android:text="确认" >
        </Button>

        <Button
            android:id="@+id/bt_cancel"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_margin="5dp"
            android:layout_weight="1"
            android:background="@drawable/custom_btn_green_selector"
            android:text="取消" >
        </Button>
    </LinearLayout>

</LinearLayout>

2. EditText 的背景是画的edittext_background 圆角矩形

edittext_background 实现

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">

    <!-- 圆角-->
    <corners android:radius="5dp" />
    <!--描边-->
    <stroke
        android:width="1dp"
        android:color="@android:color/holo_blue_light" />

</shape>

android.R.style.Theme_Material_Light_Dialog_Alert 是用来定义Dialog 样式。

        Builder builder = new AlertDialog.Builder(this,
                android.R.style.Theme_Material_Light_Dialog_Alert);

10. 自定义Loading样式对话框

• 实现效果如下：

• 实现代码如下：

    /**
     * 自定义Loading样式对话框
     ***/
    public void CustomStyleProgressDialog(View view) 

        LayoutInflater inflater = LayoutInflater.from(this);
        View v = inflater.inflate(R.layout.dialog_custom_style_progress, null);
        LinearLayout layout = (LinearLayout) v.findViewById(R.id.dialog_view);

        ImageView spaceshipImage = (ImageView) v.findViewById(R.id.img);
        TextView tipTextView = (TextView) v.findViewById(R.id.tipTextView);

        Animation hyperspaceJumpAnimation = AnimationUtils.loadAnimation(this,
                R.anim.loading_animation);

        spaceshipImage.startAnimation(hyperspaceJumpAnimation);

        Dialog loadingDialog = new Dialog(this, R.style.loading_dialog);

        // loadingDialog.setCancelable(true);//“返回键”取消 不可以用
        loadingDialog.setContentView(layout, new LinearLayout.LayoutParams(
                LinearLayout.LayoutParams.MATCH_PARENT,
                LinearLayout.LayoutParams.MATCH_PARENT));
        loadingDialog.show();
    

1. 自定义Dialog Sstyle 如下：

    <!-- 自定义loading dialog样式 -->
    <style name="loading_dialog" parent="android:style/Theme.Dialog">
        <item name="android:windowFrame">@null</item>
        <item name="android:windowNoTitle">true</item>
        <item name="android:windowBackground">@drawable/loading_bg</item>
        <item name="android:windowIsFloating">true</item>
        <item name="android:windowContentOverlay">@null</item>
    </style>

2. 自定义Dialog 样式动画如下：

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:shareInterpolator="false" >

    <!-- 自定义旋转的动画 -->
    <rotate
        android:duration="800"
        android:fromDegrees="0"
        android:interpolator="@android:anim/linear_interpolator"
        android:pivotX="50%"
        android:pivotY="50%"
        android:repeatCount="-1"
        android:repeatMode="restart"
        android:startOffset="-1"
        android:toDegrees="+360" />

</set>

3. 自定义样式的布局如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/dialog_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/loading_bg"
    android:gravity="center"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/img"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:layout_marginTop="20dp"
        android:gravity="center_horizontal"
        android:src="@drawable/loading" />

    <TextView
        android:id="@+id/tipTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:layout_marginBottom="20dp"
        android:layout_marginTop="10dp"
        android:gravity="center_horizontal"
        android:text="loading..."
        android:textColor="@android:color/holo_green_light"
        android:textSize="20sp" />

</LinearLayout>

11. 继承 DialogFragment 实现对话框

• 实现效果如下：

1.自定义继承DialogFragment 类

• 实现代码如下：

自定义继承DialogFragment 类

public class CustomDialogFragment extends DialogFragment 

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) 
        // Use the Builder class for convenient dialog construction
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setMessage("通过 DialogFragment 创建对话框")
                .setTitle("DialogFragment")
                .setPositiveButton("OK", new DialogInterface.OnClickListener() 
                    public void onClick(DialogInterface dialog, int id) 
                        Toast.makeText(getActivity(), "点击 OK",
                                Toast.LENGTH_SHORT).show();
                    
                )
                .setNegativeButton("cancle",
                        new DialogInterface.OnClickListener() 
                            public void onClick(DialogInterface dialog, int id) 
                                // User cancelled the dialog
                            
                        );
        // Create the AlertDialog object and return it
        return builder.create();
    

2. Activity 调用显示Dialog方法

    /**
     * 继承 DialogFragment 实现对话框
     * **/
    public void CustomFragmentDialog(View view) 

        CustomDialogFragment customDialogFragment = new CustomDialogFragment();
        customDialogFragment.show(getFragmentManager(), "fragment");
    

12. Activity形式的 对话框

只需创建一个Activity，并在<activity>清单文件元素中将其主题设置为 Theme.Holo.Dialog样式即可

<activity android:theme="@android:style/Theme.Holo.Dialog" >

13.倒计时 30s Dialog实现

实现效果如下：

实现代码如下：

    private TextView mShutDownTextView;
    private Handler mOffHandler;
    private Timer mShutdownTime;
    private Dialog mDialog;

    public void CountDownDialog(View view) 

        CreateShutDownDialog();

    

    private Handler mNumHandler = new Handler() 
        public void handleMessage(android.os.Message msg) 
            if (msg.what > 0) 

                // //动态显示倒计时
                mShutDownTextView
                        .setText("Warning! Battery temperature°С, phone will shutdown in "
                                + msg.what + "s");

             else 
                if (mDialog != null) 
                    mDialog.dismiss();
                
                mShutdownTime.cancel();
                Toast.makeText(getApplicationContext(), "倒计时结束", 0).show();

            
        

    ;

    private void CreateShutDownDialog() 

        mShutDownTextView = new TextView(this);
        mShutDownTextView.setLineSpacing(1.2f, 1.2f);
        mShutDownTextView.setText("");
        mShutDownTextView.setPadding(20, 20, 20, 20);
        mDialog = new AlertDialog.Builder(this).setTitle("Safety Warning")
                .setCancelable(false).setView(mShutDownTextView)
                .setPositiveButton("OK", new DialogInterface.OnClickListener() 
                    public void onClick(DialogInterface dialog, int id) 
                        mShutdownTime.cancel();

                    
                ).create();
        mDialog.show();
        mDialog.setCanceledOnTouchOutside(false);
        mShutdownTime = new Timer(true);
        TimerTask timeTask = new TimerTask() 
            int countTime = 30;

            public void run() 
                if (countTime > 0) 
                    countTime--;
                
                Message msg = new Message();
                msg.what = countTime;
                mNumHandler.sendMessage(msg);
            
        ;
        mShutdownTime.schedule(timeTask, 1000, 1000);
    

至此，本篇已结束，如有不对的地方，欢迎您的建议与指正。同时期待您的关注，感谢您的阅读，谢谢！