这是启动手电筒的代码，但是每隔1分钟就应该询问“是否继续，如果用户按下确定，然后在1分钟后再次显示ALertDialog，直到用户在警告对话框中按取消。 在这段代码中，它在1分钟后只显示1次alertdialog但如何以递归方式生成它可以有人帮忙吗？
package com.example.android.flashlight1;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
public class MainActivity extends AppCompatActivity
{
private Runnable mStatusChecker;
private int mInterval = 60000;
private Handler mHandler;
private AlertDialog.Builder alertdialog;
private boolean isLightOn=false;
private Camera camera;
private Button btn;
private Context context;
private static final ScheduledExecutorService worker =
Executors.newSingleThreadScheduledExecutor();
@Override
protected void onStop()
{
super.onStop();
if(camera!= null)
camera.release();
}
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn=(Button)findViewById(R.id.button);
context=this;
PackageManager pk= context.getPackageManager();
if(!pk.hasSystemFeature(PackageManager.FEATURE_CAMERA))
{
Log.e("err", "Device has no camera");
return;
}
camera=camera.open();
final Camera.Parameters p= camera.getParameters();
btn.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
if (isLightOn)
{
Log.i("info", "FlashLight is turn off");
p.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
camera.setParameters(p);
camera.stopPreview();
isLightOn = false;
}
else
{
Log.i("info", "FlashLight is turn On!");
p.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
camera.setParameters(p);
camera.startPreview();
isLightOn = true;
startRepeatingTask();
/* new Handler().postDelayed(new Runnable() {
//Using handler with postDelayed called runnable run method
@Override
public void run() {
//Show your Alert box here
new AlertDialog.Builder(context) // you can use getApplicationContext() or your activityname.this as context
.setTitle("Do You Want to continue")
.setMessage("Are you sure you want to continue?")
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
//Do nothing, Torch continues
//worker.schedule(run(),5, TimeUnit.SECONDS);
dialog.dismiss();
startRepeatingTask();
}
})
.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// torch off
Log.i("info", "FlashLight is turn off");
p.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
camera.setParameters(p);
camera.stopPreview();
isLightOn = false;
dialog.dismiss();
stopRepeatingTask();
}
})
// .setIcon(android.R.drawable.ic_launcher.png)
.show();
}
}, 60000); //60000milliseconds = 60 sec = 1min.
// It will show alertbox after 1 min .*/
}
}
});
alertdialog = new AlertDialog.Builder(this);
mHandler =new Handler();
mStatusChecker = new Runnable()
{
@Override
public void run()
{
try {
//
//Show your Alert box here
alertdialog
.setTitle("Do You Want to continue")
.setMessage("Are you sure you want to continue?")
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
//Do nothing, Torch continues
dialog.dismiss();
}
})
.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// torch off
Log.i("info", "FlashLight is turn off");
p.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
camera.setParameters(p);
camera.stopPreview();
isLightOn = false;
dialog.dismiss();
stopRepeatingTask();
}
})
// .setIcon(android.R.drawable.ic_launcher.png)
.show();
}
finally
{
// 100% guarantee that this always happens, even if
// your update method throws an exception
mHandler.postDelayed(mStatusChecker, mInterval);
}
}
};
}
void startRepeatingTask()
{
mStatusChecker.run();
}
void stopRepeatingTask()
{
mHandler.removeCallbacks(mStatusChecker);
}
}