Question

我正在做后台处理。同时，我想向用户显示圆形进度栏。后台进程完成后，我想隐藏圆形进度条。但是，当我在showDialog（）之后运行somethign时，它消失了。后台进程正在进行时如何显示此对话框？

MainActivity.java

import android.app.Dialog;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ProgressBar;

public class MainActivity extends AppCompatActivity {

    ProgressBar progressBar;
    int pStatus = 0;
    Handler handler = new Handler();
    public static Dialog circularProgressBarDialog;
    public static Thread circularProgressBarThread;

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



        circularProgressBarDialog = new Dialog(this);
        circularProgressBarDialog.setContentView(R.layout.dialog_circular_progressbar);
        progressBar = circularProgressBarDialog.findViewById(R.id.progressBar);
        circularProgressBarDialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
        circularProgressBarDialog.setCancelable(false);


        if(circularProgressBarThread != null && circularProgressBarThread.isAlive()){
            circularProgressBarThread.interrupt();
        }
        circularProgressBarThread = new Thread(new Runnable() {
            @Override
            public void run() {
                while (pStatus <=100) {
                    handler.post(new Runnable() {
                        @Override
                        public void run() {
                            progressBar.setProgress(pStatus);
                            Log.d("tarik","pStatus : " + pStatus);
                            if(pStatus++ >= 100){
                                pStatus = 0;
                            }
                        }
                    });

                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                }
            }
        });
        circularProgressBarThread.start();


        new Handler().post(new Runnable() {
            @Override
            public void run() {
                circularProgressBarDialog.show(); // dialog appears

                /* dialog disappears when this for loop runs!! WHY !!!!  */
                for (int i = 0; i < 200000; i++) {
                    Log.d("heavy work","1");
                }
                circularProgressBarDialog.dismiss();
                circularProgressBarThread.interrupt();
            }
        });
    }
}

custom_progressbar_drawable.xml

<?xml version="1.0" encoding="utf-8"?>
<rotate xmlns:android="http://schemas.android.com/apk/res/android"
    android:fromDegrees="-90"
    android:pivotX="50%"
    android:pivotY="50%"
    android:toDegrees="270" >

    <shape
        android:shape="ring"
        android:useLevel="false" >
        <gradient
            android:centerY="0.5"
            android:endColor="#FA5858"
            android:startColor="#0099CC"
            android:type="sweep"
            android:useLevel="false" />
    </shape>

</rotate>

dialog_circular_progressbar.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_centerInParent="true"
        android:layout_height="wrap_content">

        <ProgressBar
            android:id="@+id/progressBar"
            style="?android:attr/progressBarStyleHorizontal"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:layout_centerInParent="true"
            android:indeterminate="false"
            android:max="100"
            android:progress="0"
            android:progressDrawable="@drawable/custom_progressbar_drawable"
            android:secondaryProgress="0" />

    </RelativeLayout>
</RelativeLayout>

Answer 1

尝试对进度对话框使用setCancelabl（false）。您也可以为此目的使用异步任务。

Answer 2

尝试更换

 for (int i = 0; i < 200000; i++) {
     Log.d("heavy work","1");
 }

做一些繁重的工作。从0到200000的循环对我来说似乎并不繁重。尝试：

Thread.sleep(5000)

或增加一些延迟以表示繁重的工作。请记住，实际进度条应使用实际进度进行更新，或者将其不确定地设置为true。您可以通过在“工作”块内设置进度来完成进度的真实表示。如果您在UI线程外更新视图，请记住调用runOnUiThread（）。

显示对话框，直到后台进程完成

2 个答案: