android 之 Dialog

Posted 2020-09-20 叶常绿

android平台下对话框主要有普通对话框、选项对话框、单选多选对话框、进度对话框、日期对话框、时间对话框等。

在程序中通过开发回调方法onCreateDialog来完成对话框的创建，该方法需要传入代表对话框id参数。如果要显示对话框，则调用showDialog方法传入对话框的id来显示指定对话框。

当对话框第一次被显示时，会调用onCreateDialog方法来创建对话框实例，之后将不再重复创建该实例。每次对话框在被显示之前都会调用onPrepareDialog方法，如不重写该方法，每次显示的对话框都将是最初创建的那个。

关闭对话框可用dismiss方法实现。但如果需要让对话框在关闭之后彻底被清除，要调用removeDialog方法并传入dialog的id来彻底释放对话框。

onDismissListener方法可在关闭对话框时执行一些特定工作。

例子如下：

界面上放置四个按钮：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <TextView android:id="@+id/tv01" android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:text="@string/hello" />
    <Button android:id="@+id/bt01" android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:text="普通对话框" />
    <Button android:id="@+id/bt02" android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:text="列表对话框" />
    <Button android:id="@+id/bt03" android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:text="单选按钮对话框" />
    <Button android:id="@+id/bt04" android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:text="复选按钮对话框" />
    <Button android:id="@+id/bt05" android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:text="日期对话框" />
    <Button android:id="@+id/bt06" android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:text="时间对话框" />
    <Button android:id="@+id/bt07" android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:text="进度条对话框" />
    <DigitalClock android:text="DigitalClock"
        android:textSize="20dip" android:gravity="center" android:id="@+id/dclock01"
        android:layout_width="fill_parent" android:layout_height="wrap_content" />
    <AnalogClock android:text="AnalogClock" android:textSize="20dip"
        android:gravity="center" android:id="@+id/aclock01"
        android:layout_width="fill_parent" android:layout_height="wrap_content" />
</LinearLayout>

为每个按钮绑定OnClikListener，其中用showDialog（id）方法显示对话框：

bt01.setOnClickListener(new Button.OnClickListener(){

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
               showDialog(COMMON_DIALOG);
            }});

覆写onCreateDialog方法：

@Override
protected Dialog onCreateDialog(int id) {
    // TODO Auto-generated method stub
    Dialog dialog = null;
    switch (id) {
    case COMMON_DIALOG:
        Builder b1 = new AlertDialog.Builder(this);
        b1.setIcon(R.drawable.img01);
        b1.setTitle("普通对话框标题");
        b1.setMessage("普通对话框内容");
        b1.setPositiveButton("确定", new OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {
                // TODO Auto-generated method stub
                
                tv.setText("您选择了普通对话框");
            }
        });
        dialog = b1.create();
        break;

    case LIST_DIALOG:
        Builder b2 = new AlertDialog.Builder(this);
        b2.setIcon(R.drawable.img01);
        b2.setTitle("列表对话框标题");
        b2.setItems(R.array.msa, new DialogInterface.OnClickListener() {
            
            @Override
            public void onClick(DialogInterface dialog, int which) {
                // TODO Auto-generated method stub
                tv.setText("您选择了："+getResources().getStringArray(R.array.msa)[which]);
            }
        });
        dialog = b2.create();
        break;

/*其中R.array.msa在res/values下array.xml中：

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array name="msa">
        <item>游泳</item>
        <item>篮球</item>
        <item>足球</item>
    </string-array>
</resources>

*/

    case LIST_DIALOG_SINGLE:
        Builder b3 = new AlertDialog.Builder(this);
        b3.setIcon(R.drawable.img01);
        b3.setTitle("单选按钮对话框标题");
        b3.setSingleChoiceItems(R.array.msa, 0,new DialogInterface.OnClickListener() {
            
            @Override
            public void onClick(DialogInterface dialog, int which) {
                // TODO Auto-generated method stub
                tv.setText("您选择了："+getResources().getStringArray(R.array.msa)[which]);
            }
        });
        b3.setPositiveButton("确定", new DialogInterface.OnClickListener() {
            
            @Override
            public void onClick(DialogInterface dialog, int which) {
                // TODO Auto-generated method stub
                
            }
        });
        dialog = b3.create();
        break;

    case LIST_DIALOG_MULTIPLE:

        Builder b4 = new AlertDialog.Builder(this);
        b4.setIcon(R.drawable.img01);
        b4.setTitle("复选按钮对话框标题");
        b4.setMultiChoiceItems(R.array.msa, mulFlags,new DialogInterface.OnMultiChoiceClickListener() {
            
            @Override
            public void onClick(DialogInterface dialog, int which, boolean isChecked) {
                // TODO Auto-generated method stub
                mulFlags[which]=isChecked;
                String result="您选择了：";
                for(int i=0;i<mulFlags.length;i++){
                    if(mulFlags[i]){
                        result+=items[i]+"、";
                    }
                }
                tv.setText(result.substring(0, result.length()-1));
            }
        });
        b4.setPositiveButton("确定", new DialogInterface.OnClickListener() {
            
            @Override
            public void onClick(DialogInterface dialog, int which) {
                // TODO Auto-generated method stub
                
            }
        });
        dialog = b4.create();
        break;

case DATE_DIALOG:
            c=Calendar.getInstance();
            dialog=new DatePickerDialog(this, new DatePickerDialog.OnDateSetListener() {
                
                @Override
                public void onDateSet(DatePicker view, int year, int monthOfYear,
                        int dayOfMonth) {
                    // TODO Auto-generated method stub
                    tv.setText("您选择了"+year+"年"+monthOfYear+"月"+dayOfMonth+"日");
                }
            }, c.get(Calendar.YEAR), c.get(Calendar.MONTH), c.get(Calendar.DAY_OF_MONTH));

        case TIME_DIALOG:
            c=Calendar.getInstance();
            dialog=new TimePickerDialog(this, new TimePickerDialog.OnTimeSetListener() {

                @Override
                public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
                    // TODO Auto-generated method stub
                    tv.setText("您选择了"+hourOfDay+"时"+minute+"分");
                }
            }, c.get(Calendar.HOUR_OF_DAY), c.get(Calendar.MINUTE),false);

case PROGRESS_DIALOG:
            pd = new ProgressDialog(this);
            pd.setMax(100);
            pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
            pd.setTitle("安装进度");
            pd.setCancelable(false);
            dialog=pd;
            break;

    default:
        break;
    }
    return dialog;
}

显示进度进度条需要时刻更新进度条进度，因此需要覆写onPrepareDialpg方法：

@Override
    protected void onPrepareDialog(int id, Dialog dialog) {
        // TODO Auto-generated method stub
        super.onPrepareDialog(id, dialog);
        switch (id) {
        case PROGRESS_DIALOG:
            pd.incrementProgressBy(-pd.getProgress());
           new Thread() {//该线程负责进度对话框的进度，并发送消息至主Activity的handler对象进行更新。
                public void run() {
                    while (true) {
                        myHandler.sendEmptyMessage(INCREASE);
                        if (pd.getProgress() >= 100) {
                            break;
                        }
                        try {
                            Thread.sleep(40);
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                }
            }.start();
        }
    }

主函数中myhandler：

myHandler = new Handler() {

           @Override
            public void handleMessage(Message msg) {
                // TODO Auto-generated method stub

                switch (msg.what) {
                case INCREASE:
                    pd.incrementProgressBy(1);
                    if (pd.getProgress() >= 100) {
                        pd.dismiss();
                    }
                    break;
                }
                super.handleMessage(msg);
            }

        };