Android---常用方法

1、获取资源：  Resources res = getBaseContext().getResources();
Drawable draw=res.getDrawable(R.drawable.icon);
2、获得数组:   String[] ary = getResources().getStringArray(R.array.ary);
3、自动提示框：
String[] arrays=new String[]{"a","ab","abc","bc","bcde","ee"};
        actalert=(AutoCompleteTextView)findViewById(R.id.actalert);
        ArrayAdapter<String> adapter=new ArrayAdapter<String>(
                this,
                android.R.layout.simple_dropdown_item_1line,
                arrays);
        actalert.setAdapter(adapter);
       
       
        mactalert=(MultiAutoCompleteTextView)findViewById(R.id.mactvalert);
        mactalert.setAdapter(adapter);
// 设置多个值之间的分隔符，此处为逗号
        mactalert.setTokenizer(new MultiAutoCompleteTextView.CommaTokenizer());
4、spinner设置数据源
spncolor.setPrompt("请选择");
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
                this, R.array.attr, android.R.layout.simple_spinner_item);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spncolor.setAdapter(adapter);
5、显示当前时间：
SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss"); 
        //  将当前时间显示在TextView组件中 
        tvTime.setText("当前时间：" + sdf.format(new Date()));
6、代码添加布局文件
AbsListView.LayoutParams lp = new AbsListView.LayoutParams( 
                    ViewGroup.LayoutParams.FILL_PARENT, 64); 
 
            TextView text = new TextView(activity); 
            text.setLayoutParams(lp); 
            text.setTextSize(20); 
            text.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT); 
            text.setPadding(36, 0, 0, 0); 
            text.setText(s);
7、自定义窗口标题栏代码
  requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);//自定义标题栏
        setContentView(R.layout.main);
        //为标题栏设置一个xml布局
        getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.title_custom);
custom_title.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content">
 
    <TextView android:id="@+id/tvtitle"
         android:layout_width="wrap_content" android:layout_height="wrap_content"
         android:layout_alignParentLeft="true"></TextView>
        
    <LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content"
        android:layout_toRightOf="@+id/tvtile" android:orientation="horizontal"
        android:layout_alignParentRight="true" android:gravity="center">
       
        <Button android:text="@string/answer" android:id="@+id/btnanswer"
            android:layout_width="wrap_content" android:layout_height="wrap_content"
            android:background="@color/btn_inter" android:layout_marginRight="8dp"
            android:gravity="center" android:paddingTop="2dp"></Button>
           
         <Button android:text="@string/submit" android:id="@+id/btnsubmit"
             android:layout_width="wrap_content" android:layout_height="wrap_content"
             android:background="@color/btn_inter" android:layout_marginRight="8dp"
             android:gravity="center" android:paddingTop="2dp"></Button>
       
       
   
     </LinearLayout>
</RelativeLayout>




8、Activity仿Dialog Theme（加图标和标题其实就是Activity的icon和titile）(1)、自定义样式
<style name="Theme.CustomDialog" parent="android:style/Theme.Dialog"> 
    <item name="android:windowBackground">@drawable/filled_box</item> 
</style>
@drawable/filled_box：资源文件中新建drawable文件夹，新建filled_box样式xml
<shape xmlns:android="http://schemas.android.com/apk/res/android"> 
    <solid android:color="#f0600000"/> 
    <stroke android:width="3dp" color="#ffff8080"/> 
    <corners android:radius="3dp" /> 
    <padding android:left="10dp" android:top="10dp" 
        android:right="10dp" android:bottom="10dp" /> 
</shape>
(2)Manifest.xml中配置Acitivity样式
<activity android:name=".Main"
                  android:label="@string/app_name"
                  android:theme="@android:style/Theme.Dialog">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
(3)为Activity设置图标
//设定窗口模式(仿Dialog中的icon，带有一个左图标)
        requestWindowFeature(Window.FEATURE_LEFT_ICON);
       
        setContentView(R.layout.main);
        //设置图片资源
         getWindow().setFeatureDrawableResource(Window.FEATURE_LEFT_ICON
           , R.drawable.icon);
9、从一个Activity1到另一个Activity2，当在第二个Activity2按返回键不出现Activity1的做法是在打开Activity2的同时关闭Activity1
Intent intent = new Intent(Main.this, fowardwidget.class);
        startActivity(intent);
        finish();
10、允许TextView的文本值拼接
(1)允许在TextView的文本值后添加buffer text
tv.setText(tv.getText(),TextView.BufferType.EDITABLE);
(2)使用Editable对象添加buffer text
Editable text=(Editable)tv.getText();
text.append("editable");
text.append("\n"):
11、如果历史栈中包含Activity，打开此Activity从栈中放到栈顶层而不是从新打开Activity
Intent intent = new Intent(ReorderFour.this, ReorderTwo.class);
intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
startActivity(intent);
12、避免输入法面板遮挡，在manifest.xml中activity中设置android:windowSoftInputMode
android:windowSoftInputMode="stateVisible|adjustResize"
13、获取当前手机壁纸和设置手机壁纸（wallpaper）(1)获取当前壁纸
WallpaperManager wm=WallpaperManager.getInstance(this);
Drawable wallpaper=wpm.getDrawable();
(2)设置当前壁纸，同时要添加壁纸设置权限
imapaper.setDrawingCacheEnabled(true);
Drawable drawale=this.getResources().getDrawable(R.drawable.bg);
imapaper.setImageDrawable(drawale);
wpm.setBitmap(imapaper.getDrawingCache());
<uses-permission android:name="android.permission.SET_WALLPAPER"></uses-permission>
14、常见通过系统服务得到的实例化对象
NotificationManager nm=(NotificationManager)getSystemService(NOTIFICATION_SERVICE);
15、检查网络是否连接
  //检查网络是否连接
    public boolean checkIntent(){
        ConnectivityManager mannager=(ConnectivityManager)
              this.getSystemService(CONNECTIVITY_SERVICE);
        NetworkInfo info=mannager.getActiveNetworkInfo();
        if(info==null || !info.isConnected()){
            return false;
        }
        if(info.isRoaming()){
            return true;
        }
        return true;
    }
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>






16、从资源文件中（asset）读取文本文档
//获得输入流
InputStream in=getAssets().open("read_asset.txt");
int size=in.available();
//将输入流读到字节数组中（内存）
byte[] buffer=new byte[size];
in.read(buffer);
in.close();
String text=new String(buffer);
17、TextView、Button等设置文本滚动（跑马灯效果），控件必须获得焦点才能有滚动效果，并且文字长度大于控件长度
    android:singleLine="true"
    android:ellipsize="marquee"
    android:focusable="true"
    android:marqueeRepeatLimit="marquee_forever"
//marquee_forever:一直滚动下去，n(整数）：滚动n次
18、TextView文本添加下划线
TextView textView = (TextView)findViewById(R.id.testView);   
textView.setText(Html.fromHtml("<u>"+"hahaha"+"</u>"));
19、TextView添加图片
String src=""+R.drawable.qq;
       
        Html.ImageGetter imageGetter =new ImageGetter() {
            Drawable draw=null;
            @Override
            public Drawable getDrawable(String source) {
                // TODO Auto-generated method stub
                int id=Integer.parseInt(source.trim());
                draw=getResources().getDrawable(id);
                draw.setBounds(0, 0, draw.getIntrinsicWidth(), draw.getIntrinsicHeight());
                return draw;
            }
        };
        tvquestion.append(Html.fromHtml("<img src="+src+"", imageGetter, null));
20、秒转成00：00:00
  int hour=time/60/60%60;
            int minute = time/60%60;
            int second = time%60;
            String strhour=hour<10 ? "0" + hour : "" + hour;
            String strminutes=minute<10 ? "0" + minute : "" + minute;
            String strseconds=second < 10 ? "0" + second : "" + second;
            tvtimer.setText(strhour+":"+strminutes+":"+strseconds);
21、TextView添加滚动条
<ScrollView android:id="@+id/sv_e8_question"
        android:layout_width="fill_parent" android:layout_height="180dp"
        android:scrollbarStyle="outsideOverlay">
            <TextView android:text="@string/question" android:id="@+id/tv_e8_question"
                android:layout_width="fill_parent" android:layout_height="wrap_content"
                android:paddingTop="5dp" android:paddingLeft="5dp"></TextView>
    </ScrollView>
22、Activity自动销毁时调用onSaveInstanceState()方法保存配置信息:可多Activity共享
  @Override
    public void onSaveInstanceState(Bundle outState){
        SharedPreferences.Editor editor=getSharedPreferences("sp_timer", 0).edit();
        editor.putInt(arg0, arg1);
        super.onSaveInstanceState(outState);
    }
单个Activity保存
  @Override
    public void onSaveInstanceState(Bundle outState){
        SharedPreferences.Editor editor=this.getPreferences(0).edit();
        editor.putInt(arg0, arg1);
        super.onSaveInstanceState(outState);
    }