Android運行時許可權

　　在Android6.0以後，Google將許可權分為了兩類，一類為正常許可權（Normal Permission），一類為危險許可權（Dangerous Permission）。對於正常正常許可權，只需在Manifest文件裡面申請即可，但對於危險許可權，需要運行時動態申請。

危險許可權包括以下：

動態許可權申請：

　　1、在manifest文件裡面配置所有需要申請的許可權（包括普通許可權和危險許可權）

　　2、確保工程TargetSdkVersion版本在23以上（因為動態許可權是針對23以上的版本設計的，如果TargetSdkVersion低於23，相關介面將會失效，比如ActivityCompat.checkSelfPermission將始終返回0）

　　3、確保目標設備為Android6.0及以上

　　4、檢查許可權：ActivityCompat.checkSelfPermission檢查許可權是否被允許。如果許可權被拒絕，在使用ActivityCompat.shouldShowRequestPermissionRationale檢查許可權是否被徹底拒絕。

　　5、許可權申請：如果許可權沒有被徹底拒絕，則可以使用ActivityCompat.requestPermissions申請許可權

　　6、後續處理：當用戶處理完許可權請求後，可以通過onRequestPermissionsResult獲取到用戶處理的結果

示例代碼：

　　檢查TargetSdkVersion和目標設備API版本：

　　private static int getTargetSdkVersion(Activity activity){
        int targetSdkVersion = 0;
        Context context = activity.getApplicationContext();
        try {  
            final PackageInfo info = context.getPackageManager().getPackageInfo(context.getPackageName(), 0);  
            targetSdkVersion = info.applicationInfo.targetSdkVersion;  
        } catch (PackageManager.NameNotFoundException e) {  
            e.printStackTrace();  
        }  
        return targetSdkVersion;
    }
    
    private static boolean checkRuntimePermissionAvailable(Activity activity){
        // Always return true for API version < M, let the system deal with the permissions
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
            Log.w("Permission", "API version < M, return true by default");
            return false;
        }
        // Always return true for target sdk version < M, let the system deal with the permissions
        if (getTargetSdkVersion(activity) < Build.VERSION_CODES.M) {
            Log.w("Permission", "Target sdk version < M, return true by default");
            return false;
        }
        return true;
    }

　　獲得被拒絕的許可權：

　　@SuppressLint("NewApi")
    private static String[] getDeniedPermissions(Activity activity, String[] permissions, boolean isAll) {
        List<String> deniedPermissionList = new ArrayList<String>();
        Context context = activity.getApplicationContext();
        for (String permission : permissions){
            if (ActivityCompat.checkSelfPermission(context, permission) == PackageManager.PERMISSION_GRANTED){
                Log.i("Permission", "\"" + permission + "\" has been granted");
            } else {
                if (ActivityCompat.shouldShowRequestPermissionRationale(thisClass, permission)){
                    deniedPermissionList.add(permission);
                    Log.w("Permission", "\"" + permission + "\" was denied");
                }else{
                    if (isAll){
                        deniedPermissionList.add(permission);
                    }
                    Log.w("Permission", "\"" + permission + "\" was denied completely");
                }
            }
        }
        
        String[] deniedPermissions = new String[deniedPermissionList.size()];
        deniedPermissions = deniedPermissionList.toArray(deniedPermissions);

        return deniedPermissions;
    }

　　申請被拒絕的許可權：

　　@SuppressLint("NewApi")
    private static void requestPermissions(Activity activity, int requestCode, String[] deniedPermissions){
        for( String permission : deniedPermissions ){
            Log.i("Permission", "Requesting permission \"" + permission + "\"");
        }
        ActivityCompat.requestPermissions(activity, deniedPermissions, requestCode);
    }

　　許可權申請的後續處理：

    @SuppressLint("NewApi") 
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        // TODO Auto-generated method stub
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        boolean isAllGranted = true;
        switch( requestCode ){
        case 1:
            for ( int result : grantResults){
                if (result != PackageManager.PERMISSION_GRANTED){
                    isAllGranted = false;
                    break;
                }
            }
            break;
        }
        
        if (isAllGranted){
            // All permissions are granted
            Log.i("Permission", "All permissions have been granted");
        }else{
            // There is at least a permission which aren't granted
            Log.w("Permission", "There is at least a permission which aren't granted");
        }
    }