Android Tips(一)

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判断设备是否是大屏设备

只需在相应分辨率的value配置文件下写入不同的值，如：
在/values/cofig.xml 文件中写入：

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<bool name="is_large_tablet">false</bool>

在/values-sw720p/cofig.xml 文件中写入：

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<bool name="is_large_tablet">true</bool>

然后在方法中调用：

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public static boolean isScreenLarge(Resources res) {

    return res.getBoolean(R.bool.is_large_tablet);

}

判断是否横屏

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public static boolean isScreenLandscape(Context context) {
    return context.getResources().getConfiguration().orientation ==
        Configuration.ORIENTATION_LANDSCAPE;
}

判断某个包名的应用是否已安装

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public static boolean haveInstallApp(Context context,String packageName) {
    if(TextUtils.isEmpty(packageName)) {
        return false;
    }
    // get packagemanager
    PackageManager packageManager =context.getPackageManager();
    // 获取所有已安装程序的包信息
    List<PackageInfo> info = packageManager.getInstalledPackages(0);
    if (info != null) {
        for (int i = 0; i < info.size(); i++) {
            String installPackageName = info.get(i).packageName;
            if(packageName.equals(installPackageName)) {
                return true;
            }
        }
    }
    return false;
}

获取当前程序可用内存

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/**
 * 获取当前可用内存，返回数据以字节为单位。
 *  
 * @param context
 *            可传入应用程序上下文。
 * @return 当前可用内存。
 */  
private static long getAvailableMemory(Context context) {  
    ActivityManager.MemoryInfo mi = new ActivityManager.MemoryInfo();  
    getActivityManager(context).getMemoryInfo(mi);  
    return mi.availMem;  
}

获取状态栏的高度

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/**
 * 用于获取状态栏的高度。
 *  
 * @return 返回状态栏高度的像素值。
 */  
private int getStatusBarHeight() {  
    if (statusBarHeight == 0) {  
        try {  
            Class<?> c = Class.forName("com.android.internal.R$dimen");  
            Object o = c.newInstance();  
            Field field = c.getField("status_bar_height");  
            int x = (Integer) field.get(o);  
            statusBarHeight = getResources().getDimensionPixelSize(x);  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
    }  
    return statusBarHeight;  
}

获取所有桌面应用程序包名

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/**
 * 获得属于桌面的应用的应用包名称
 *  
 * @return 返回包含所有包名的字符串列表
 */  
private List<String> getHomes() {  
    List<String> names = new ArrayList<String>();  
    PackageManager packageManager = this.getPackageManager();  
    Intent intent = new Intent(Intent.ACTION_MAIN);  
    intent.addCategory(Intent.CATEGORY_HOME);  
    List<ResolveInfo> resolveInfo = packageManager.queryIntentActivities(intent,  
            PackageManager.MATCH_DEFAULT_ONLY);  
    for (ResolveInfo ri : resolveInfo) {  
        names.add(ri.activityInfo.packageName);  
    }  
    return names;  
}

获取软键盘按键（Enter go等），并实现自定义功能

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    edittext.setOnEditorActionListener(new TextView.OnEditorActionListener() {  

            @Override  
            public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {  
                /*判断是否是“GO”键*/  
                if(actionId == EditorInfo.IME_ACTION_GO){  
                    /*隐藏软键盘*/  
                    InputMethodManager imm = (InputMethodManager) v  
                            .getContext().getSystemService(  
                                    Context.INPUT_METHOD_SERVICE);  
                    if (imm.isActive()) {  
                        imm.hideSoftInputFromWindow(  
                                v.getApplicationWindowToken(), 0);  
                    }  

                    edittext.setText("success");  
                    webview.loadUrl(URL);  

                    return true;  
                }  
                return false;  
            }  
        });

---

    <EditText  
        android:id="@+id/edittext"  
        android:layout_width="match_parent"  
        android:layout_height="wrap_content"  
        android:singleLine="true"  
        android:imeOptions="actionSearch"/>  
    actionNone : 回车键，按下后光标到下一行
    actionGo ： Go，
    actionSearch ： 放大镜
    actionSend ： Send
    actionNext ： Next
    actionDone ： Done，确定/完成，隐藏软键盘，即使不是最后一个文本输入框

获取栈顶Activity

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   public static String getClassNameOnStackTop(Context context) {
	ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
	ComponentName cn = am.getRunningTasks(1).get(0).topActivity;
	String className = cn.getClassName();
	LogUtil.d("top activity=" + className);
	return className;
}

获取屏幕方向

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private int getDeviceOrientation(Context context) {
    WindowManager windowManager =  (WindowManager)
            context.getSystemService(Context.WINDOW_SERVICE);
    Resources resources = context.getResources();
    DisplayMetrics dm = resources.getDisplayMetrics();
    Configuration config = resources.getConfiguration();
    int rotation = windowManager.getDefaultDisplay().getRotation();
    boolean isLandscape = (config.orientation == Configuration.ORIENTATION_LANDSCAPE) &&
            (rotation == Surface.ROTATION_0 || rotation == Surface.ROTATION_180);
    boolean isRotatedPortrait = (config.orientation == Configuration.ORIENTATION_PORTRAIT) &&
            (rotation == Surface.ROTATION_90 || rotation == Surface.ROTATION_270);
    if (isLandscape || isRotatedPortrait) {
        return CellLayout.LANDSCAPE;
    } else {
        return CellLayout.PORTRAIT;
    }
}

屏蔽Home键

重写onAttachedToWindow

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@Override
public void onAttachedToWindow() {
    this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD); super.onAttachedToWindow(); }  	
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (KeyEvent.KEYCODE_HOME == keyCode) {
            Toast.makeText(getApplicationContext(), "按了HOME 键...",Toast.LENGTH_LONG).show();

        }
    return super.onKeyDown(keyCode, event); //return true则将home键点击事件拦截
}

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