Android自定义可以随意拖动的ImageView和TextView

来源：互联网发布：热血传奇mac版编辑：程序博客网时间：2024/05/01 20:41

Android开发中，有时候我们需要让控件可以随着手指的移动而跟随移动的效果，例如实现任意摆放的水印图片等。

下面是自定义的一种控件，可以实现这种效果。

上代码：

import android.content.Context;
import android.util.AttributeSet;
import android.widget.ImageView;
import android.view.MotionEvent;

public class MoveImageView extends ImageView
{

private int lastX = 0;
private int lastY = 0;

private static final int screenWidth = 720;//屏幕宽度
private static final int screenHeight = 1280;//屏幕高度

public MoveImageView(Context context, AttributeSet attrs) {
super(context, attrs);
}

@Override
public boolean onTouchEvent(MotionEvent event)
{
switch (event.getAction())
{
case MotionEvent.ACTION_DOWN:
lastX = (int) event.getRawX();
lastY = (int) event.getRawY();
break;
case MotionEvent.ACTION_MOVE:
int dx =(int)event.getRawX() - lastX;
int dy =(int)event.getRawY() - lastY;

int left = getLeft() + dx;
int top = getTop() + dy;
int right = getRight() + dx;
int bottom = getBottom() + dy;
if(left < 0){
left = 0;
right = left + getWidth();
}
if(right > screenWidth){
right = screenWidth;
left = right - getWidth();
}
if(top < 0){
top = 0;
bottom = top + getHeight();
}
if(bottom > screenHeight){
bottom = screenHeight;
top = bottom - getHeight();
}
layout(left, top, right, bottom);
lastX = (int) event.getRawX();
lastY = (int) event.getRawY();
break;
case MotionEvent.ACTION_UP:
break;
default:
break;
}
return true;
}

}

如上代码所示，自定义了一个控件类MoveImageView，继承ImageView，然后在xml文件中，将需要移动的ImageView，用这个MoveImageView代替即可。

同理，可以拖动的TextView代码如下：

import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.TextView;

public class MoveTextView extends TextView{

private static final String TAG = "MoveTextView";

private int lastX = 0;
private int lastY = 0;

private static final int screenWidth = 720;
private static final int screenHeight = 1280;

public MoveTextView(Context context, AttributeSet attrs) {
super(context, attrs);
}

@Override
public boolean onTouchEvent(MotionEvent event)
{
switch (event.getAction())
{
case MotionEvent.ACTION_DOWN:
lastX = (int) event.getRawX();
lastY = (int) event.getRawY();
break;
case MotionEvent.ACTION_MOVE:
int dx =(int)event.getRawX() - lastX;
int dy =(int)event.getRawY() - lastY;

int left = getLeft() + dx;
int top = getTop() + dy;
int right = getRight() + dx;
int bottom = getBottom() + dy;
if(left < 0){
left = 0;
right = left + getWidth();
}
if(right > screenWidth){
right = screenWidth;
left = right - getWidth();
}
if(top < 0){
top = 0;
bottom = top + getHeight();
}
if(bottom > screenHeight){
bottom = screenHeight;
top = bottom - getHeight();
}
layout(left, top, right, bottom);
lastX = (int) event.getRawX();
lastY = (int) event.getRawY();
break;
case MotionEvent.ACTION_UP:
break;
default:
break;
}
return true;
}
}

相关的源代码链接：点击下载Android源代码

0 0