Question

我正在尝试在Android应用程序上请求READ_EXTERNAL_STORAGE的权限。我的问题是没有显示对话框，因此也不会调用“onRequestPermissionsResult”。我在这里做错了吗？我点了这个链接：Developer Android

这是我的代码：

public class AccountActivity extends AppCompatActivity {

    protected TextView changeProfileImgBtn;
    private static final int SELECTED_PICTURE = 1;
    private static final int F = 101;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_account);

        changeProfileImgBtn = (TextView) findViewById(R.id.accountChangeProfileImgBtn);

        changeProfileImgBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if (ContextCompat.checkSelfPermission(AccountActivity.this,
                        Manifest.permission.READ_EXTERNAL_STORAGE)
                        != PackageManager.PERMISSION_GRANTED) {

                    if (ActivityCompat.shouldShowRequestPermissionRationale(AccountActivity.this,
                                Manifest.permission.READ_EXTERNAL_STORAGE)) {
                         System.out.println("shouldShowRequestPermissionRationale");

                    } else {
                        ActivityCompat.requestPermissions(AccountActivity.this,
                                new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
                                F);

                        System.out.println("REQUEST");

                    }
                } else {
                    Intent i = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
                    startActivityForResult(i, SELECTED_PICTURE);
                }
            }
        });
    }

    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           @NonNull String permissions[], @NonNull int[] grantResults) {

        System.out.println("onRequestPermissionsResult");
        switch (requestCode) {
            case F: {
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                    System.out.println("GRANTED");

                    Intent i = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
                    startActivityForResult(i, SELECTED_PICTURE);

                } else {
                    System.out.println("DENIED");
                }
                return;
            }

            // other 'case' lines to check for other
            // permissions this app might request
        }
    }
}

正如您在Log ActivityCompat.requestPermissions（...）上看到的那样，打印出“REQUEST”。永远不会打印“shouldShowRequestPermissionRationale”，无论我正在运行什么设备。 “onRequestPermissionsResult”都没有打印出来。

D/ViewRootImpl: ViewPostImeInputStage processPointer 0
D/ViewRootImpl: ViewPostImeInputStage processPointer 1
I/System.out: REQUEST
I/Timeline: Timeline: Activity_idle id: android.os.BinderProxy@ee9f27b time:106175669

我已将其包含在我的清单文件中：

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

非常感谢任何帮助。

Answer 1

已更新：您的清单中是否已请求权限？您只能请求清单中的权限。

此处的文档：https://developer.android.com/guide/topics/manifest/manifest-intro.html

Answer 2

使用此类使用公共类进行所有权限。

public class Utility1 {


public static class Utility {
    public static final int MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE = 123;
    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
    public static boolean checkPermission(final Context context)
    {
        int currentAPIVersion = Build.VERSION.SDK_INT;
        if(currentAPIVersion>=android.os.Build.VERSION_CODES.M)
        {
            if (ContextCompat.checkSelfPermission(context, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                if (ActivityCompat.shouldShowRequestPermissionRationale((Activity) context, Manifest.permission.READ_EXTERNAL_STORAGE)) {
                    AlertDialog.Builder alertBuilder = new AlertDialog.Builder(context);
                    alertBuilder.setCancelable(true);
                    alertBuilder.setTitle("Permission necessary");
                    alertBuilder.setMessage("External storage permission is necessary");
                    alertBuilder.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                        @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
                        public void onClick(DialogInterface dialog, int which) {
                            ActivityCompat.requestPermissions((Activity) context, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE);
                        }
                    });
                    AlertDialog alert = alertBuilder.create();
                    alert.show();
                } else {
                    ActivityCompat.requestPermissions((Activity) context, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE);
                }
                return false;
            } else {
                return true;
            }
        } else {
            return true;
        }
    }
}

}

在您需要检查权限的主类中使用此行。

 boolean result = Utility1.Utility.checkPermission(MainActivity.this);

Answer 3

确保uses-permission位于manifest但application部分之外。您甚至可以尝试在“应该显示基本原理”块中请求许可：

if (ActivityCompat.shouldShowRequestPermissionRationale(AccountActivity.this,
                    Manifest.permission.READ_EXTERNAL_STORAGE)) {
    ActivityCompat.requestPermissions(AccountActivity.this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, F);
}

为了更简单，您可以使用一些第三方帮助程序代码，例如我自己的代码：PermissionHelper

请求权限对话框未显示

3 个答案: