java - 应用程序在请求用户读写权限时关闭

Question

我在我的应用程序中遇到问题，我的应用程序需要读写权限，但每当我的应用程序第一次打开时，我的应用程序崩溃并关闭，然后它会在后台请求许可，然后我需要再次启动它，然后它就可以正常工作。我仅在第一次运行时遇到问题。

这是我的代码

主要 Activity

        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
        checkPermissions();
    }


    @RequiresApi(api = Build.VERSION_CODES.M)
private void checkPermissions(){

    if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE)
            != PackageManager.PERMISSION_GRANTED) {

        // Should we show an explanation?
        if (shouldShowRequestPermissionRationale(
                Manifest.permission.READ_EXTERNAL_STORAGE)) {
            // Explain to the user why we need to read the contacts
        }

        requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
                1052);

        // MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE is an
        // app-defined int constant that should be quite unique

        return;
    }
     /*   if (ContextCompat.checkSelfPermission(this,
                android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
                != android.content.pm.PackageManager.PERMISSION_GRANTED||
                ContextCompat.checkSelfPermission(this,
                        Manifest.permission.READ_EXTERNAL_STORAGE)
                        != android.content.pm.PackageManager.PERMISSION_GRANTED)
            ActivityCompat.requestPermissions(this,
                    new String[]{
                            Manifest.permission.WRITE_EXTERNAL_STORAGE,
                            android.Manifest.permission.READ_EXTERNAL_STORAGE,
                    },
                    1052);*/



}
public void onRequestPermissionsResult(int requestCode,
                                       String permissions[], int[] grantResults) {

    switch (requestCode) {
        case 1052: {
            // If request is cancelled, the result arrays are empty.
            if (grantResults.length > 0
                    && grantResults[0] == android.content.pm.PackageManager.PERMISSION_GRANTED
                    && grantResults[1] == android.content.pm.PackageManager.PERMISSION_GRANTED)
            {
                Toast.makeText(this, "Enjoy This app", Toast.LENGTH_SHORT).show();
            }
            else {

                android.widget.Toast.makeText(this, "Permission Denied, without your permission we cant share or download images to your device", android.widget.Toast.LENGTH_LONG).show();
                // Permission denied - Show a message to inform the user that this app only works
                // with these permissions granted
            }
        }

    }
}

Answer 1

您需要通过启动一个新 Activity 并在该新 Activity 中编写上述所有代码来请求许可。我在一个新的android项目中复制了这个问题并验证了这一点。

您需要做的是创建另一个 Activity ，一个专门为请求权限而创建的 Activity 。让它成为Main2Activity.java。您的 MainActivity.java 将是

public class MainActivity extends AppCompatActivity {

@RequiresApi(api = Build.VERSION_CODES.M)
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE)
            != PackageManager.PERMISSION_GRANTED) {
        startActivity(new Intent(MainActivity.this, Main2Activity.class));
    }
}
}

那么你的 Main2Activity.java 将是

public class Main2Activity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main2);
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
        checkPermissions();
    }
}
@RequiresApi(api = Build.VERSION_CODES.M)
private void checkPermissions(){

    if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE)
            != PackageManager.PERMISSION_GRANTED) {

        // Should we show an explanation?
        if (shouldShowRequestPermissionRationale(
                Manifest.permission.READ_EXTERNAL_STORAGE)) {
            // Explain to the user why we need to read the contacts
        }

        requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
                1052);

        // MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE is an
        // app-defined int constant that should be quite unique

        return;
    }
 /*   if (ContextCompat.checkSelfPermission(this,
            android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
            != android.content.pm.PackageManager.PERMISSION_GRANTED||
            ContextCompat.checkSelfPermission(this,
                    Manifest.permission.READ_EXTERNAL_STORAGE)
                    != android.content.pm.PackageManager.PERMISSION_GRANTED)
        ActivityCompat.requestPermissions(this,
                new String[]{
                        Manifest.permission.WRITE_EXTERNAL_STORAGE,
                        android.Manifest.permission.READ_EXTERNAL_STORAGE,
                },
                1052);*/



}
public void onRequestPermissionsResult(int requestCode,
                                       String permissions[], int[] grantResults) {

    switch (requestCode) {
        case 1052: {
            // If request is cancelled, the result arrays are empty.
            if (grantResults.length > 0
                    && (grantResults[0] == android.content.pm.PackageManager.PERMISSION_GRANTED
                    || grantResults[1] == android.content.pm.PackageManager.PERMISSION_GRANTED))
            {
                Toast.makeText(this, "Enjoy This app", Toast.LENGTH_SHORT).show();
                startActivity(new Intent(Main2Activity.this, MainActivity.class));
                finish();
            }
            else {

                android.widget.Toast.makeText(this, "Permission Denied, without your permission we cant share or download images to your device", android.widget.Toast.LENGTH_LONG).show();
                // Permission denied - Show a message to inform the user that this app only works
                // with these permissions granted
            }
        }

    }
}
}

请注意，在 Main2Activity.java 中，我进行了编辑

if (grantResults.length > 0
                    && (grantResults[0] == android.content.pm.PackageManager.PERMISSION_GRANTED
                    || grantResults[1] == android.content.pm.PackageManager.PERMISSION_GRANTED))
            {
                Toast.makeText(this, "Enjoy This app", Toast.LENGTH_SHORT).show();
                startActivity(new Intent(Main2Activity.this, MainActivity.class));
                finish();
            }

1. 要显示 Toast，android.content.pm.PackageManager.PERMISSION_GRANTED 将位于 grantResults[0] 或 grantResults[1] 中，但不能同时位于两者中。
2. 我使用了 startActivity() 和 finish() 函数，因为在获得许可后，专门为许可而创建的此 Activity 将关闭并打开 MainActivity.java。