我正在翻阅关于Android m中的新权限模型的官方文档。它讨论了shouldShowRequestPermissionRationale()函数,如果应用程序之前请求了此权限,并且用户拒绝了请求,该函数将返回true。如果用户在过去拒绝了权限请求并选择Don't ask again选项,则此方法返回false。
但是我们如何区分以下两种情况呢?
案例1:应用程序没有权限,之前也没有向用户请求过权限。在这种情况下,shouldShowRequestPermissionRationale()将返回false,因为这是我们第一次请求用户。
情况2:用户拒绝了权限并选择了“不要再问了”,在这种情况下shouldShowRequestPermissionRationale()将返回false。
我想把用户发送到案例2中的应用设置页面。我怎么微分这两种情况呢?
这段代码要求用户在运行时请求权限,
如果用户允许,执行结果方法,
如果用户拒绝,它会用描述和用户拒绝再次询问(它会用说明再次询问),
但如果用户选择永远不会再问。
它处理永不再问,显示打开设置选项与说明。
public String storagePermissions = Manifest.permission.READ_EXTERNAL_STORAGE;
private static final int REQUEST_ACCESS =101;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if(checkSelfPermission(storagePermissions)== PackageManager.PERMISSION_GRANTED){
result(); // result is your block of code
}else {
requestPermissions(new String[]{storagePermissions},REQUEST_ACCESS);
}
}
else{
result(); //so if user is lower than api verison M, no permission is requested
}
}
private void showMessageOKCancel(String message, DialogInterface.OnClickListener okListener) {
new AlertDialog.Builder(MainActivity.this)
.setMessage(message)
.setTitle("Hi User..")
.setPositiveButton("Ok", okListener)
.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) { //idea calling showMessage funtion again
Snackbar mySnackbar = Snackbar.make( findViewById(R.id.coordinatorlayout),"You Press Cancel.. ", Snackbar.LENGTH_INDEFINITE);
mySnackbar.setAction("Exit", new cancelButton());
mySnackbar.show();
}
})
.create()
.show();
}
private void result(){
//your code
}
@RequiresApi(api = Build.VERSION_CODES.M)
public class NeverAskAgain implements View.OnClickListener{
@Override
public void onClick(View view)
{
goToSettings();
}
}
@RequiresApi(api = Build.VERSION_CODES.M)
private void goToSettings() {
Intent myAppSettings = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.parse("package:" + getPackageName()));
finish();
myAppSettings.addCategory(Intent.CATEGORY_DEFAULT);
myAppSettings.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivityForResult(myAppSettings, REQUEST_APP_SETTINGS);
}
public class cancelButton implements View.OnClickListener{
@Override
public void onClick(View view){
Toast.makeText(MainActivity.this,"To use this app , you must grant storage permission",Toast.LENGTH_SHORT);
finish();
}
}
@Override
@RequiresApi(api = Build.VERSION_CODES.M)
public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[], @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode,permissions,grantResults);
switch(requestCode) {
case REQUEST_ACCESS:
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission is granted
result();
break;
}
else if (!shouldShowRequestPermissionRationale(permissions[0])){
showMessageOKCancel("You choose Never Ask Again,option",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Snackbar mySnackbar = Snackbar.make(findViewById(R.id.coordinatorlayout), "Permission=>Storage=>On", Snackbar.LENGTH_INDEFINITE);
mySnackbar.setAction("Settings", new NeverAskAgain());
mySnackbar.show();
}
});
break;
}
else {
showMessageOKCancel("You Denid permission Request..",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
requestPermissions(new String[]{storagePermissions}, REQUEST_ACCESS);
}
});
break;
}
}
}
“M Preview 1”后,如果第一次弹出对话框,则没有“Never ask again”复选框。
如果用户拒绝权限请求,第二次请求权限时,权限对话框中会出现“Never ask again”复选框。
所以逻辑应该是这样的:
Request permission:
if (ContextCompat.checkSelfPermission(context, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(context, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, REQUEST_CODE);
} else {
//Do the stuff that requires permission...
}
Check if the permission was denied or granted in onRequestPermissionsResult.
If the permission was denied previously, this time there will be a Never ask again checkbox in the permission dialog.
Call shouldShowRequestPermissionRationale to see if the user checked Never ask again. shouldShowRequestPermissionRationale method returns false only if the user selected Never ask again or device policy prohibits the app from having that permission:
if (grantResults.length > 0){
if(grantResults[0] == PackageManager.PERMISSION_GRANTED) {
//Do the stuff that requires permission...
}else if (grantResults[0] == PackageManager.PERMISSION_DENIED){
// Should we show an explanation?
if (ActivityCompat.shouldShowRequestPermissionRationale(context, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
//Show permission explanation dialog...
}else{
//Never ask again selected, or device policy prohibits the app from having that permission.
//So, disable that feature, or fall back to another situation...
}
}
}
因此,如果用户勾选了“永不再问”,您将不必跟踪。