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如何正确暂停应用程序直到权限请求完成?

android-permissions asynchronous android java

MW2023 · 技术社区 · 7 年前

我正在写一个应用程序,它唯一的功能就是充当蓝牙低能量接收器。如果用户不允许使用BLE,那么应用程序就没用了。当应用程序第一次启动时,我希望它向用户请求Locations权限(因为Android需要它才能启动BLE)。我打开了“权限”对话框,但当用户阅读对话框、启动BLEScanner等时,应用程序的其余部分仍在继续。我希望应用程序暂停,而用户正在阅读对话框,并决定做什么。以下是我的设置:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, REQUEST_CODE);
        }

        //More UI preparation stuff

    @Override
    public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
        switch (requestCode) {
            case REQUEST_CODE: {
                if (permissions[0].equals(Manifest.permission.ACCESS_COARSE_LOCATION)) {
                    if (grantResults[0] != PackageManager.PERMISSION_GRANTED) {
                        PermissionDialog newDialog = new PermissionDialog();
                        newDialog.show(getSupportFragmentManager(), "Request Location Permission");
                }
            }
        }
    }

其中“PermissionDialog”是另一个类,它使用DialogFragment来解释应用程序为什么需要权限,然后关闭/重新启动应用程序。在这种情况下,应用程序的其余部分继续,试图在用户仍在阅读弹出的权限对话框时执行蓝牙操作!天真地说,我以为可以使用同步锁来完成,如下所示,但在本例中,从不调用回调:

private final Object initLock = new Object();
public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, REQUEST_CODE);
        }

        Log.i("Lock", "At the lock!");

        try {
            synchronized (initLock) {
                initLock.wait();
            }
        }
        catch (InterruptedException e) {
            //TODO find out what to do here
        }

        Log.i("Lock", "Past the lock!");


    @Override
    public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
        switch (requestCode) {
            case REQUEST_CODE: {
                if (permissions[0].equals(Manifest.permission.ACCESS_COARSE_LOCATION)) {
                    if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                        synchronized (initLock){
                            initLock.notify();
                        }
                    }
                    else{
                        PermissionDialog newDialog = new PermissionDialog();
                        newDialog.show(getSupportFragmentManager(), "Request Location Permission");
                    }
                }
            }
        }
    }

正确的方法是什么?我有一些想法,但都是空想。我是否需要创建另一个继承AppCompatActivity的类来执行权限并将其称为线程?但是我怎么知道onRequestPermissionResult回调会去哪里呢?我不知所措。

3 回复 | 直到 7 年前

Nabin Bhandari 7 年前

把密码放在你的电脑里 //More UI preparation stuff 一种新方法。在权限之后,说' init() '

private void init(){
    //More UI preparation stuff
}

然后在里面 onCreate ,如果已授予权限,请调用 init();

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, REQUEST_CODE);

    } else {
        init();
    }
}

现在在内部处理用户的响应 onRequestPermissionsResult -如果用户已授权,则初始化UI,否则阻止该功能和/或将问题通知用户。

@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
    switch (requestCode) {
        case REQUEST_CODE: {
            if (permissions[0].equals(Manifest.permission.ACCESS_COARSE_LOCATION)) {
                if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    init();

                } else{
                    PermissionDialog newDialog = new PermissionDialog();
                    newDialog.show(getSupportFragmentManager(), "Request Location Permission");
                }
            }
        }
    }
}

PS:出于同样的目的,我准备了一个库,使这个过程更容易。看一看 my library.

Seraph Gabriel 7 年前

并添加此注释 @AfterPermissionGranted 在要运行的方法之前例如:

AfterPermissionGranted(PERMISSION_REQUESTCODE_BASE)
private void requestPerminssions(){
    if(EasyPermissions.hasPermissions(this,PERMISSIONS)){
        int hasCityData=config.getInt("isDataEmpty",0);
        if(hasCityData==0){
            new CountryInfoThread().execute();
        }else {
            new LocalPositionThread().execute();
        }
    }
}

MW2023 7 年前

private boolean readyToStart = false;

这样:

@Override
    protected void onCreate(Bundle savedInstanceState) {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, REQUEST_CODE);
        }
        else{
            readyToStart = true;
        }
    }



@Override
    protected void onResume() {
        super.onResume();
        if (readyToStart) {
            startBluetooth();
        }
    }

@Override
    public void onRequestPermissionsResult(int requestCode, String permissions[],
                                           int[] grantResults) {
        Log.i("Permission", "Callback made");
        switch (requestCode) {
            case REQUEST_CODE: {
                if (permissions[0].equals(Manifest.permission.ACCESS_COARSE_LOCATION)) {
                    if (grantResults[0] != PackageManager.PERMISSION_GRANTED) {
                        PermissionDialog newDialog = new PermissionDialog();
                        newDialog.show(getSupportFragmentManager(), "Request Location Permission");
                    }
                    else{
                        startBluetooth();
                    }
                }
            }
        }
    }