java - 杀死所有线程后退出 Activity android

Question

我正在尝试玩进度条。我有一个(如下)简单的 Activity ，当我调用 Progress(N) 时，它会一个接一个地运行进度条 N 次。它工作得很好，但我面临的问题是，如果我按后退按钮。我进入了 mainActivity，但进度条(线程)仍然在后台一个接一个地运行。一旦它们完成 N 个循环， Intent 就会被调用，而我要做的任何事情都会被这个 LOOP_OVER Activity 打断。

我尝试自己解决这个问题。我尝试使用 Thread 类的变量(在我直接这样做之前)。并尝试在 onDestroy() 甚至在调用 Intent 之前中断它，但它没有帮助。我该怎么办？

public class Loop extends Activity {

    private ProgressBar progressBar;
    private CircleProgress circleProgress;
    private int progressStatus = 0;
    private Handler handler = new Handler();

    private TextView myView;
    private int started = 0, doneLoop=0;
    private Thread th;


    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_loop);

        progressBar = (ProgressBar) findViewById(R.id.progressBar1);
        circleProgress = (CircleProgress) findViewById(R.id.circle_progress);

        myView = (TextView) findViewById(R.id.instruction);

        progressBar.setScaleY(3f);
        // Start long running operation in a background thread

        Progress(3);

    }

    @Override
    public void onDestroy() {
        // Below, everything I am just 
        th.interrupt();
        Loop.this.finish();
        Thread.currentThread().interrupt();
        super.onDestroy();
    }

    public void Progress(final int numberOfRuns){
//        QueView.setText(Que);
        if(numberOfRuns == 0){
            th.interrupt();
            Intent myIntent = new Intent(Loop.this, LOOP_OVER.class);
            startActivity(myIntent);
            super.onDestroy();
            finish();
        }
        th = new Thread(new Runnable() {
            public void run() {
                genNextSet();
                while (progressStatus < 100) {
                    progressStatus += 1;
                    // Update the progress bar and display the
                    //current value in the text view
                    handler.post(new Runnable() {
                        public void run() {
                            circleProgress.setProgress(progressStatus);
                            progressBar.setProgress(progressStatus);
                            textView.setText(progressStatus+"/"+progressBar.getMax());
                        }
                    });
                    try {
                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                // TODO Auto-generated method stub

                                myView.setText(Que);
                            }
                        });
                        // Sleep for 200 milliseconds.
                        //Just to display the progress slowly
                        Thread.sleep(30);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                progressStatus = 0;

                Progress(numberOfRuns - 1);
            }
        });

        th.start();
    }


    private void genNextSet() {
        // so some cool here!
    }
}

Answer 1

您可以想象一个在所有线程之间共享的类变量。

尝试添加如下内容:

private Boolean LOOP = true;

然后

while (progressStatus < 100 && LOOP) {

和

@Override
public void onBackPressed() { 
    LOOP = false
}

还有

if(LOOP == true){
    // call intent
}
finish();