Android开发中自定义ProgressBar控件的方法示例

public class ProgressView extends ImageView {
  private Drawable maskDraw;
  /**
   * 加载的进度 0-100
   */
  private int mProcess = 20;
  public ProgressView(Context context, AttributeSet attrs) {
    super(context, attrs);
    maskDraw = context.getResources().getDrawable(R.drawable.red_bg);
  }
  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    // 保存当前画笔的状态
    canvas.save();
    int topline = (int) (getHeight() - getHeight() * getProcess() / 100);
    /*
     * canvas 剪切出一个区域，使在这个区域里面的内容是有效的，区域之外是无效的。
     */
    canvas.clipRect(0, topline, getWidth(), getHeight());
    maskDraw.draw(canvas);
    // 恢复到之前保存的状态
    canvas.restore();
  }
  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    maskDraw.setBounds(0, 0, getWidth(), getHeight());
  }
  public float getProcess() {
    return mProcess;
  }
  /**
   * 设置新的进度以后，自动刷新
   */
  public void setProgress(int mProcess) {
    if (mProcess > 100) {
      this.mProcess = 100;
    }
    if (mProcess < 0) {
      this.mProcess = 0;
    }
    this.mProcess = mProcess;
    invalidate();
  }
}

public class ProgressActivity extends Activity {
  private ProgressView piv;
  private int pivDeep = 0;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_progressview);
    piv = (ProgressView) findViewById(R.id.my_pro_iv);
    handler.sendEmptyMessage(2);
  }
  private Handler handler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
      switch (msg.what) {
      case 1:
        piv.setProgress(pivDeep);
        break;
      case 2:
        new Thread() {
          public void run() {
            while (true) {
              pivDeep = (pivDeep + 5) % 100;
              handler.sendEmptyMessage(1);
              try {
                Thread.sleep(200);
              } catch (InterruptedException e) {
                e.printStackTrace();
              }
            }
          };
        }.start();
        break;
      default:
        break;
      }
    }
  };
}