Android实现在屏幕上移动图片的方法

本文实例讲述了android实现在屏幕上移动图片的方法。分享给大家供大家参考。具体实现方法如下：

1. speed.java文件：

package net.obviam.droidz.model.components;
public class speed {
  public static final int direction_right = 1;
  public static final int direction_left = -1;
  public static final int direction_up  = -1;
  public static final int direction_down = 1;
  private float xv = 1;  // velocity value on the x axis
  private float yv = 1;  // velocity value on the y axis
  private int xdirection = direction_right;
  private int ydirection = direction_down;
  public speed() {
    this.xv = 1;
    this.yv = 1;
  }
  public speed(float xv, float yv) {
    this.xv = xv;
    this.yv = yv;
  }
  public float getxv() {
    return xv;
  }
  public void setxv(float xv) {
    this.xv = xv;
  }
  public float getyv() {
    return yv;
  }
  public void setyv(float yv) {
    this.yv = yv;
  }
  public int getxdirection() {
    return xdirection;
  }
  public void setxdirection(int xdirection) {
    this.xdirection = xdirection;
  }
  public int getydirection() {
    return ydirection;
  }
  public void setydirection(int ydirection) {
    this.ydirection = ydirection;
  }
  // changes the direction on the x axis
  public void togglexdirection() {
    xdirection = xdirection * -1;
  }
  // changes the direction on the y axis
  public void toggleydirection() {
    ydirection = ydirection * -1;
  }
}

2. main.java文件：

public void run() {
  canvas canvas;
  log.d(tag, "starting game loop");
  while (running) {
    canvas = null;
    // try locking the canvas for exclusive pixel editing
    // in the surface
    try {
      canvas = this.surfaceholder.lockcanvas();
      synchronized (surfaceholder) {
        // update game state
        this.gamepanel.update();
        // render state to the screen
        // draws the canvas on the panel
        this.gamepanel.render(canvas);
      }
    } finally {
      // in case of an exception the surface is not left in
      // an inconsistent state
      if (canvas != null) {
        surfaceholder.unlockcanvasandpost(canvas);
      }
    }  // end finally
  }
}
public void update() {
  // check collision with right wall if heading right
  if (droid.getspeed().getxdirection() == speed.direction_right
      && droid.getx() + droid.getbitmap().getwidth() / 2 >= getwidth()) {
    droid.getspeed().togglexdirection();
  }
  // check collision with left wall if heading left
  if (droid.getspeed().getxdirection() == speed.direction_left
      && droid.getx() - droid.getbitmap().getwidth() / 2 <= 0) {
    droid.getspeed().togglexdirection();
  }
  // check collision with bottom wall if heading down
  if (droid.getspeed().getydirection() == speed.direction_down
      && droid.gety() + droid.getbitmap().getheight() / 2 >= getheight()) {
    droid.getspeed().toggleydirection();
  }
  // check collision with top wall if heading up
  if (droid.getspeed().getydirection() == speed.direction_up
      && droid.gety() - droid.getbitmap().getheight() / 2 <= 0) {
    droid.getspeed().toggleydirection();
  }
  // update the lone droid
  droid.update();
}

希望本文所述对大家的android程序设计有所帮助。