Android 新特性学习

Posted 2022-11-25

概述

又到了项目学习的时间，今天所要学习的是一个新闻客户端，微阅，项目地址如下
​​​微阅​​​
我们开始学习吧。

笔记

首先我们来集成一个Bug管理平台

​​微阅Bug管理​​

ToolBar

<android.support.v7.widget.Toolbar
   android:id="@+id/my_toolbar"
   android:layout_
   android:layout_
   android:background="?attr/colorPrimary"
   android:elevation="4dp"
   android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
   app:popupTheme="@style/ThemeOverlay.AppCompat.Light"/>

MaterialDesign推荐AppBar设置elevation为4dp.

点击按钮返回主页面

<!-- A child of the main activity -->
    <activity
        android:name="com.example.myfirstapp.MyChildActivity"
        android:label="@string/title_activity_child"
        android:parentActivityName="com.example.myfirstapp.MainActivity" >

        <!-- Parent activity meta-data to support 4.0 and lower -->
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.example.myfirstapp.MainActivity" />
    </activity>

ActionBar ab = getSupportActionBar();

    // Enable the Up button
    ab.setDisplayHomeAsUpEnabled(true);

<android.support.design.widget.TextInputLayout
            android:id="@+id/textInput"
            android:layout_
            android:layout_>
                <EditText
                    android:layout_
                    android:layout_
                    android:textColor="@android:color/black"/>
        </android.support.design.widget.TextInputLayout>
        <android.support.design.widget.TextInputLayout
            android:id="@+id/textInput2"
            android:layout_
            android:layout_>
                <EditText
                    android:layout_
                    android:layout_
                    android:textColor="@android:color/black"/>
        </android.support.design.widget.TextInputLayout>

final TextInputLayout inputLayout = (TextInputLayout) findViewById(R.id.textInput);
        final TextInputLayout inputLayout2 = (TextInputLayout) findViewById(R.id.textInput2);
        inputLayout.setHint("请输入姓名");
        inputLayout2.setHint("请输入地址");
        EditText editText = inputLayout.getEditText();
        EditText editText2 = inputLayout2.getEditText();
        editText.addTextChangedListener(new TextWatcher() 
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) 
            
            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) 
                if (s.length()>4)
                    inputLayout.setErrorEnabled(true);
                    Toast.makeText(MainActivity.this, "超过", Toast.LENGTH_SHORT).show();
                    inputLayout.setError("姓名长度不能超过4个");
                else
                    inputLayout.setError(null);//这样这只可以保证每次都出现错误提示
                    inputLayout.setErrorEnabled(false);
                
            
            @Override
            public void afterTextChanged(Editable s) 
            
        );
        editText2.addTextChangedListener(new TextWatcher() 
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) 

            

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) 
                if (s.length()>4)
                    inputLayout2.setErrorEnabled(true);
                    Toast.makeText(MainActivity.this, "超过", Toast.LENGTH_SHORT).show();
                    inputLayout2.setError("地址长度不能超过4个");
                else
                    inputLayout2.setErrorEnabled(false);//只出现一次错误提示
                
            

            @Override
            public void afterTextChanged(Editable s) 

            
        );

//不自动消失
        snackbar = Snackbar.make(inputLayout, "弹出提示", Snackbar.LENGTH_INDEFINITE);
    
    public void click(View view)
        snackbar.show();
        snackbar.setAction("取消", new View.OnClickListener() 
            @Override
            public void onClick(View v) 
                snackbar.dismiss();
            
        );
    

TabLayout

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/fl_parent"
    android:layout_
    android:layout_
    android:orientation="vertical">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_
        android:layout_
        android:background="#00ff00"
        android:elevation="4dp"
        android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light"></android.support.v7.widget.Toolbar>

    <android.support.design.widget.TabLayout
        android:id="@+id/tabs"
        android:layout_
        android:layout_
        app:layout_scrollFlags="scroll"
        app:tabIndicatorColor="@android:color/holo_green_light"
        app:tabSelectedTextColor="@android:color/holo_red_dark"
        app:tabTextColor="@android:color/black" />

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_
        android:layout_></android.support.v4.view.ViewPager>
</LinearLayout>

• TabLayout一般和ViewPager结合使用
• 代码中设置了指示器的颜色，选中和未选中文字的颜色

public class TabFragment extends Fragment 
    private View view;
    private TextView textView;
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) 
        view = inflater.inflate(R.layout.tab_item, null);
        textView = (TextView) view.findViewById(R.id.tv_item);
        return view;
    

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) 
        super.onActivityCreated(savedInstanceState);
        //获取传过来的参数
        String content = getArguments().getString("content", "");
        textView.setText(content);
    

public class TabFragmentAdapter extends FragmentStatePagerAdapter 
    private List<Fragment> fragments;
    private List<String> titles;
    public TabFragmentAdapter(FragmentManager fm,List<Fragment> fragments,List<String> titles) 
        super(fm);
        this.fragments = fragments;
        this.titles = titles;
    

    @Override
    public Fragment getItem(int position) 
        return fragments.get(position);
    

    @Override
    public int getCount() 
        return fragments.size();
    

    /**
     * 获取Tab的标题
     * @param position
     * @return
     */
    @Override
    public CharSequence getPageTitle(int position) 
        return titles.get(position);
    

private ViewPager viewPager;
    List<String> tabTitles = new ArrayList<>();
    List<Fragment> fragments = new ArrayList<>();
    private TabLayout tabLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        ActionBar bar = getSupportActionBar();
        bar.setDisplayHomeAsUpEnabled(true);
        tabLayout = (TabLayout) findViewById(R.id.tabs);
        viewPager = (ViewPager) findViewById(R.id.viewpager);
        tabTitles.add("Tab1");
        tabTitles.add("Tab2");
        tabTitles.add("Tab3");
        tabTitles.add("Tab4");
        tabTitles.add("Tab5");
        tabTitles.add("Tab6");
        tabLayout.setTabMode(TabLayout.MODE_SCROLLABLE);
        tabLayout.addTab(tabLayout.newTab().setText(tabTitles.get(0)));
        tabLayout.addTab(tabLayout.newTab().setText(tabTitles.get(1)));
        tabLayout.addTab(tabLayout.newTab().setText(tabTitles.get(2)));
        for (int i = 0; i < tabTitles.size(); i++) 
            Fragment fragment = new TabFragment();
            Bundle bundle = new Bundle();
            bundle.putString("content","内容"+i);
            fragment.setArguments(bundle);
            fragments.add(fragment);
        
        TabFragmentAdapter adapter = new TabFragmentAdapter(getSupportFragmentManager(),fragments,tabTitles);
        viewPager.setAdapter(adapter);
        tabLayout.setupWithViewPager(viewPager);
        tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() 
            @Override
            public void onTabSelected(TabLayout.Tab tab) 
                int position = tab.getPosition();
                //viewpager平滑过度。不是瞬间切换
                viewPager.setCurrentItem(position,false);
            

            @Override
            public void onTabUnselected(TabLayout.Tab tab) 

            

            @Override
            public void onTabReselected(TabLayout.Tab tab) 

            
        );

TabLayout更改样式的代码

public class FragmentOne extends Fragment 
    private TabLayout tabLayout;
    private List<String>  titleList ;
    private String[] titleString = "英超","西甲","法甲","德甲","意甲","中超";
    private TextView itemView;
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) 
        View view = View.inflate(getContext(),R.layout.fg_one,null);
        tabLayout = (TabLayout) view.findViewById(R.id.tabs);
        tabLayout.setTabMode(TabLayout.MODE_FIXED);
        initTitle();
        return view;
    

    public void initTitle()
        titleList = Arrays.asList(titleString);
        for (int i = 0; i < titleList.size(); i++) 
            TabLayout.Tab tab = tabLayout.newTab();
            tabLayout.setBackgroundResource(R.drawable.tab_bg);
            tab.setCustomView(R.layout.tab_item_layout);
            itemView = (TextView) tab.getCustomView().findViewById(R.id.tab_txt);
            itemView.setText(titleList.get(i));
            tabLayout.addTab(tab);
            if(i == 0)
                setTabColor(tab,android.R.color.white);
            
        
        tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() 
            @Override
            public void onTabSelected(TabLayout.Tab tab) 
               setTabColor(tab,android.R.color.white);
            

            @Override
            public void onTabUnselected(TabLayout.Tab tab) 
                    setTabColor(tab,android.R.color.black);
            

            @Override
            public void onTabReselected(TabLayout.Tab tab) 
            
        );
    
    public void setTabColor(TabLayout.Tab tab,int color)
        TextView selectViiew = (TextView) tab.getCustomView().findViewById(R.id.tab_txt);
        selectViiew.setTextColor(getResources().getColor(color));