Android M(6.0) 權限爬坑之旅

有一篇全面介紹Android M 運行時權限文章寫的非常全面(翻譯的)：Android M 新的運行時權限開發者需要知道的一切，但是實施過程中還是遇到一些坑。

坑一：用Android5.0編譯的apk，在Android6.0上運行完全沒有問題。

1. 在Android6.0以上才需要在運行時請求權限，在舊Android版本上保留原有邏輯，安裝時授予權限。
2. 用舊版本sdk編譯的apk，都使用舊版本權限方式，安裝時授予權限。(也就是說：兼容舊版本)
3. 用Android6.0(targetSdkVersion 23)編譯apk才需要處理新的權限問題。
4. 還有一個蛋疼的問題：程序運行當中，用戶關閉了權限，會發生什么？（還未知）
</ol>

坑二：藍牙掃描需要位置權限

BluetoothUtils: Permission denial: Need ACCESS_COARSE_LOCATION or ACCESS_FINE_LOCATION permission to get scan results

如何申請一個權限：用ACCESS_COARSE_LOCATION舉栗子

1. Manifest添加權限

Android6.0分了幾種權限：Normal Permissions(安裝時自動授權，用戶也不能取消權限) and Dangerous Permissions

    <!-- Android6.0 藍牙掃描才需要-->
    <uses-permission-sdk-23 android:name="android.permission.ACCESS_COARSE_LOCATION"/>

2. 請求權限

//判斷是否有權限
// Here, thisActivity is the current activity
if (ContextCompat.checkSelfPermission(thisActivity,
                Manifest.permission.ACCESS_COARSE_LOCATION)
        != PackageManager.PERMISSION_GRANTED)

//請求權限
ActivityCompat.requestPermissions(thisActivity,
                new String[]{Manifest.permission.ACCESS_COARSE_LOCATION},
                MY_PERMISSIONS_REQUEST_ACCESS_COARSE_LOCATION);
//判斷是否需要 向用戶解釋，為什么要申請該權限
ActivityCompat.shouldShowRequestPermissionRationale(thisActivity,
                Manifest.permission.READ_CONTACTS)
//權限申請結果
onRequestPermissionsResult(int requestCode,
        String permissions[], int[] grantResults)</pre> 
坑三：Fragment請求權限 

//如果使用ActivityCompat.requestPermissions，不會調用onRequestPermissionsResult()
//請求權限
requestPermissions(new String[]{Manifest.permission.ACCESS_COARSE_LOCATION},
                MY_PERMISSIONS_REQUEST_ACCESS_COARSE_LOCATION);
//判斷是否需要 向用戶解釋，為什么要申請該權限
shouldShowRequestPermissionRationale(Manifest.permission.READ_CONTACTS)
 
坑四：WRITE_SETTINGS權限怎么處理 

android.permission.WRITE_SETTINGS不能自動授權，也不能運行時請求授權，咋整啊？通過打開Intent來讓用戶設置。貌似SETTINGS的權限只能這么處理，from CommonsWare research Android 6.0 changes. 

    /**


 * An app can use this method to check if it is currently allowed to write or modify system
 * settings. In order to gain write access to the system settings, an app must declare the
 * {@link android.Manifest.permission#WRITE_SETTINGS} permission in its manifest. If it is
 * currently disallowed, it can prompt the user to grant it this capability through a
 * management UI by sending an Intent with action
 * {@link android.provider.Settings#ACTION_MANAGE_WRITE_SETTINGS}.
 *
 * @param context A context
 * @return true if the calling app can write to system settings, false otherwise
 */
 if(!Settings.System.canWrite(this)){
      Intent intent = new Intent(Settings.ACTION_MANAGE_WRITE_SETTINGS,
                Uri.parse("package:" + getPackageName()));
      startActivityForResult(intent, REQUEST_CODE);
 } 


@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_CODE) {
        if (Settings.System.canWrite(this)) {
            //檢查返回結果
            Toast.makeText(MainActivity.this, "WRITE_SETTINGS permission granted", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(MainActivity.this, "WRITE_SETTINGS permission not granted", Toast.LENGTH_SHORT).show();
        }
    }
}</pre></div>

來自：https://yanlu.me/android-m6-0-permission-chasm/