如图是效果图，移动ImageView时ImageView的位置会发生改变，并且双击的时候ImageView会水平居中
package com.org.demo.youku; import com.org.wangfeng.R; import android.app.Activity; import android.content.SharedPreferences; import android.content.SharedPreferences.Editor; import android.os.Bundle; import android.os.SystemClock; import android.view.MotionEvent; import android.view.View; import android.view.View.OnTouchListener; import android.widget.ImageView; import android.widget.RelativeLayout; import android.widget.RelativeLayout.LayoutParams; import android.widget.TextView; public class MainDrag extends Activity { private TextView tv_top; private TextView tv_bottom; private ImageView iv_drag; // private ViewPager dPager; private int startX; private int startY; private SharedPreferences sPreferences; long[] mHits = new long[2];// 数组长度表示要点击的次数 @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.maindrag); tv_top = (TextView) findViewById(R.id.tv_top); tv_bottom = (TextView) findViewById(R.id.tv_bottom); iv_drag = (ImageView) findViewById(R.id.iv_drag); // 计算手机屏的宽和高 final int winWidth = getWindowManager().getDefaultDisplay().getWidth(); final int winHeight = getWindowManager().getDefaultDisplay() .getHeight(); // 用来记录坐标 下次进入实现移动后的坐标 sPreferences = getSharedPreferences("config", Activity.MODE_PRIVATE); int getLastX = sPreferences.getInt("lastX", 0); int getLastY = sPreferences.getInt("lastY", 0); // onMeasure(测量view), onLayout(安放位置), onDraw(绘制) // ivDrag.layout(getLastX, getLastY, getLastX + ivDrag.getWidth(), // getLastY + ivDrag.getHeight());//不能用这个方法,因为还没有测量完成,就不能安放位置 if (getLastY > winHeight / 2) {// 上边显示,下边隐藏 tv_top.setVisibility(View.VISIBLE); tv_bottom.setVisibility(View.INVISIBLE); } else { tv_top.setVisibility(View.INVISIBLE); tv_bottom.setVisibility(View.VISIBLE); } RelativeLayout.LayoutParams layoutParams = (LayoutParams) iv_drag .getLayoutParams(); layoutParams.leftMargin = getLastX;// 设置左边距 layoutParams.topMargin = getLastY;// 设置top边距 iv_drag.setLayoutParams(layoutParams); // 重新设置位置 // 设置双击居中的事件 iv_drag.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View arg0) { // TODO Auto-generated method stub System.arraycopy(mHits, 1, mHits, 0, mHits.length - 1); mHits[mHits.length - 1] = SystemClock.uptimeMillis();// 开机后开始计算的时间 if (mHits[0] >= (SystemClock.uptimeMillis() - 500)) { // 把图片居中 System.out.println("双击了 要居中"); iv_drag.layout(winWidth / 2 - iv_drag.getWidth() / 2, iv_drag.getTop(), winWidth / 2 + iv_drag.getWidth() / 2, iv_drag.getBottom()); } } }); // 设置触摸监听事件 iv_drag.setOnTouchListener(new OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { // TODO Auto-generated method stub switch (event.getAction()) { case MotionEvent.ACTION_DOWN: // 初始化起点的坐标 startX = (int) event.getRawX(); startY = (int) event.getRawY(); break; case MotionEvent.ACTION_MOVE: // 移动后的坐标 int endX = (int) event.getRawX(); int endY = (int) event.getRawY(); // 计算移动的偏移量 int dx = endX - startX; int dy = endY - startY; // 更新后左上右下的距离 int l = iv_drag.getLeft() + dx; int t = iv_drag.getTop() + dy; int r = iv_drag.getRight() + dx; int b = iv_drag.getBottom() + dy; // 判断是否超出屏幕边界, 注意状态栏的高度 if (l < 0 || r > winWidth || t < 0 || b > winHeight) { System.out.println("不符要求"); break; } // 根据图片位置,决定提示框显示和隐藏 if (t > winHeight / 2) {// 上边显示,下边隐藏 tv_top.setVisibility(View.VISIBLE); tv_bottom.setVisibility(View.INVISIBLE); } else { tv_top.setVisibility(View.INVISIBLE); tv_bottom.setVisibility(View.VISIBLE); } // 更新界面 iv_drag.layout(l, t, r, b); // 重新初始化起点坐标 startX = (int) event.getRawX(); startY = (int) event.getRawY(); System.out.println("ACTION_MOVE坐标x" + startX + "---iv_drag.getLeft()---" + iv_drag.getLeft()); break; case MotionEvent.ACTION_UP: // 记录移动后的坐标 System.out.println("ACTION_UP" + "iv_drag.getLeft()---" + iv_drag.getLeft() + "---iv_drag.getTop()---" + iv_drag.getTop()); Editor edit = sPreferences.edit(); edit.putInt("lastX", iv_drag.getLeft()); edit.putInt("lastY", iv_drag.getTop()); edit.commit(); break; default: break; } return false;// 事件要向下传递,让onclick(双击事件)可以响应 } }); } }
<?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" > <TextView android:id="@+id/tv_top" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" android:background="@drawable/png_3" android:gravity="center" android:padding="10dp" android:text="按住提示框拖到任意位置 按手机返回键立即生效" android:textColor="#000" android:textSize="16sp" /> <TextView android:id="@+id/tv_bottom" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_centerHorizontal="true" android:background="@drawable/png_3" android:gravity="center" android:padding="10dp" android:text="按住提示框拖到任意位置 按手机返回键立即生效" android:textColor="#000" android:textSize="16sp" android:visibility="invisible" /> <ImageView android:id="@+id/iv_drag" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="90dp" android:contentDescription="@null" android:src="@drawable/drag" /> </RelativeLayout>