Android请求运行时权限不起作用
Android请求运行时权限不起作用
提问于 2018-06-12 08:53:52
当我尝试在Android模拟器上请求运行时权限时遇到了一些问题。我正在尝试做的是在点击按钮时，在进入我的异步任务类之前请求对外部存储的读写权限。
下面是我的代码：
private static final int PERMISSION_REQUEST_CODE = 1;
String readPermission = Manifest.permission.READ_EXTERNAL_STORAGE;
String writePermission = Manifest.permission.WRITE_EXTERNAL_STORAGE;
@Click(R.id.buttonVersionUpgrade)
void buttonVersionUpgradeClicked(View v) {
if (!checkPermission(readPermission) || !checkPermission(writePermission)) {
requestPermission(readPermission);
requestPermission(writePermission);
}
// async task here
}
private boolean checkPermission(String permission){
if (Build.VERSION.SDK_INT >= 23) {
int result = ContextCompat.checkSelfPermission(getApplicationContext(), permission);
if (result == PackageManager.PERMISSION_GRANTED){
return true;
} else {
return false;
}
} else {
return true;
}
}
private void requestPermission(String permission){
if (ActivityCompat.shouldShowRequestPermissionRationale(this, permission)){
Toast.makeText(getApplicationContext(), "Read/Write external storage permission allows us to read/write data. Please allow in App Settings for additional functionality.",Toast.LENGTH_LONG).show();
}
ActivityCompat.requestPermissions(this, new String[]{permission},PERMISSION_REQUEST_CODE);
}
@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
switch (requestCode) {
case PERMISSION_REQUEST_CODE:
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
Toast.makeText(getApplicationContext(), "Permission Granted. Now you can read/write data.",
Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getApplicationContext(),"Permission Denied. You cannot read/write data.",
Toast.LENGTH_LONG).show();
}
break;
}
}但是，在移动到异步任务执行之前，它不会提示用户提供权限，这会导致应用程序崩溃。它只在应用程序崩溃时提示用户。有什么想法吗？
谢谢!
回答 1
Stack Overflow用户
回答已采纳
发布于 2018-06-12 08:56:39
这是因为ActivityCompat.requestPermissions不是同步调用。操作系统将显示弹出窗口(实际上是一个活动)，随后的语句将被执行。
因为这两个权限对于您同时请求它们是强制的。
if (!checkPermission(readPermission) || !checkPermission(writePermission)) {
requestPermission(new String[] {readPermission,writePermission});
} else{
//Run Async task directly since the permissions are already granted
}
private void requestPermission(String[] permissions){
if (ActivityCompat.shouldShowRequestPermissionRationale(this, permissions[0])||ActivityCompat.shouldShowRequestPermissionRationale(this, permissions[1])){
Toast.makeText(getApplicationContext(), "Read/Write external storage permission allows us to read/write data. Please allow in App Settings for additional functionality.",Toast.LENGTH_LONG).show();
}
ActivityCompat.requestPermissions(this, permissions,PERMISSION_REQUEST_CODE);
}ActivityCompat.requestPermissions(this，permissions，requestCode)；
将AsyncTask执行移到onRequestPermissionsResult，如下所示：
@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
switch (requestCode) {
case PERMISSION_REQUEST_CODE:
if (verifyGrantResults(grantResults)) {
Toast.makeText(getApplicationContext(), "Permission Granted. Now you can read/write data.",
Toast.LENGTH_LONG).show();
//start Async Task here
} else {
Toast.makeText(getApplicationContext(),"Permission Denied. You cannot read/write data.",
Toast.LENGTH_LONG).show();
}
break;
}
}
private boolean verifyGrantResults(final int[] grantResults) {
boolean permissionsGranted = true;
if (grantResults.length > 0) {
for (int result : grantResults) {
if (result == PackageManager.PERMISSION_DENIED) {
permissionsGranted = false;
}
}
return permissionsGranted;
}
return false;
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/50807882
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