Android:ProgressBar 进度条

进度条的运用还算比较多，比如说我们下载APP时，都会有进度条。不多说，直接上代码。

MainActivity.java

package com.example.progressbartest;

import android.os.Bundle;
import android.os.Handler;
import android.app.Activity;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

    private Button startButton;
    private Button stopButton;
    private TextView result;
    private ProgressBar MyProgressBar;
    private final static int Value=5;
    private int i=0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.progress);
        setTitle("ProgressBar");

        startButton=(Button)findViewById(R.id.startButton);
        stopButton=(Button)findViewById(R.id.stopButton);
        result=(TextView)findViewById(R.id.result);
        MyProgressBar=(ProgressBar)findViewById(R.id.firstProgressBar);

        MyProgressBar.setVisibility(0);//刚开始设置进度条可见
        MyProgressBar.setVisibility(View.GONE);//不可见
        MyProgressBar.setVisibility(View.VISIBLE);//可见
        MyProgressBar.setVisibility(View.INVISIBLE);//不可见
        MyProgressBar.setVisibility(View.VISIBLE);//可见

        startButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                if(i>=MyProgressBar.getMax()){
                    i=0;
                }
                result.setText(((double)i/MyProgressBar.getMax()*100)+"%");
                handler.post(progressBarThread);
            }
        });

        stopButton.setOnClickListener(new View.OnClickListener()
         {
            @Override
            public void onClick(View v) {
                handler.removeCallbacks(progressBarThread);         
            }
        });
    }

    //创建Handler对象
    Handler handler=new Handler();

    //创建线程对象
    MyRunnable progressBarThread=new MyRunnable();
    class MyRunnable implements Runnable{
        @Override
        public void run() {
            i+=Value;
            //每隔1秒调用一次progressBarThread线程
            handler.postDelayed(progressBarThread, 1000);
            MyProgressBar.setProgress(i);
            MyProgressBar.setSecondaryProgress(i+Value);
            result.setText(((double)i/MyProgressBar.getMax()*100)+"%");
            if(i>=MyProgressBar.getMax()){ 
                handler.removeCallbacks(progressBarThread); 
                test();
            }
        }
    }

    public void test(){
        Toast.makeText(this, "progressBar is max", 1).show();
    }
}

通过创建Handler对象管理线程，完成功能。

上面重复的设置setVisibility，只是为了让自己搞清楚setVisibility的属性值情况。

通过查看源码：

public void setVisibility(int v) {
        if (getVisibility() != v) {
            super.setVisibility(v);

            if (mIndeterminate) {
                // let's be nice with the UI thread
                if (v == GONE || v == INVISIBLE) {
                    stopAnimation();
                } else {
                    startAnimation();
                }
            }
        }
    }