Android编程之控件可拖动的实现方法

private static final String TAG = "DragViewActivity";private ImageView iv_dv_view;private TextView tv_drag_view;private int startx;private int starty;private SharedPreferences sp;@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    requestWindowFeature(Window.FEATURE_NO_TITLE);    setContentView(R.layout.dragview);//   Drawable drawable = new ColorDrawable(color.transparent);//   getWindow().setBackgroundDrawable(drawable);    iv_dv_view = (ImageView) this.findViewById(R.id.iv_dv_view);    tv_drag_view = (TextView) this.findViewById(R.id.tv_drag_view);    sp = this.getSharedPreferences("config", Context.MODE_PRIVATE);    iv_dv_view.setOnTouchListener(this);  }  @Override  protected void onResume() {    super.onResume();    int x = sp.getInt("lastx", 0);    int y = sp.getInt("lasty", 0);//   iv_dv_view.layout(iv_dv_view.getLeft() + x, iv_dv_view.getTop() + y,//       iv_dv_view.getRight() + x, iv_dv_view.getBottom() + y);//   iv_dv_view.invalidate();//界面重新渲染    LayoutParams params = (LayoutParams) iv_dv_view.getLayoutParams();    params.leftMargin = x;    params.topMargin = y;    iv_dv_view.setLayoutParams(params);  }  @Override  public boolean onTouch(View v, MotionEvent event) {    switch (v.getId()) {    // 如果手指放在imageView上拖动    case R.id.iv_dv_view:      // event.getRawX(); //获取手指第一次接触屏幕在x方向的坐标      switch (event.getAction()) {      case MotionEvent.ACTION_DOWN:// 获取手指第一次接触屏幕        startx = (int) event.getRawX();        starty = (int) event.getRawY();        break;      case MotionEvent.ACTION_MOVE:// 手指在屏幕上移动对应的事件        int x = (int) event.getRawX();        int y = (int) event.getRawY();        if (y < 400) {          // 设置TextView在窗体的下面          tv_drag_view.layout(tv_drag_view.getLeft(), 420,              tv_drag_view.getRight(), 440);        } else {          tv_drag_view.layout(tv_drag_view.getLeft(), 60,              tv_drag_view.getRight(), 80);        }        // 获取手指移动的距离        int dx = x - startx;        int dy = y - starty;        // 得到imageView最开始的各顶点的坐标        int l = iv_dv_view.getLeft();        int r = iv_dv_view.getRight();        int t = iv_dv_view.getTop();        int b = iv_dv_view.getBottom();        // 更改imageView在窗体的位置        iv_dv_view.layout(l + dx, t + dy, r + dx, b + dy);        // 获取移动后的位置        startx = (int) event.getRawX();        starty = (int) event.getRawY();        break;      case MotionEvent.ACTION_UP:// 手指离开屏幕对应事件        Log.i(TAG, "手指离开屏幕");        // 记录最后图片在窗体的位置        int lasty = iv_dv_view.getTop();        int lastx = iv_dv_view.getLeft();        Editor editor = sp.edit();        editor.putInt("lasty", lasty);        editor.putInt("lastx", lastx);        editor.commit();        break;      }      break;    }    return true;// 不会中断触摸事件的返回}

<?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"  android:background="#cc000000" ><ImageView   android:layout_width="160dip"   android:layout_height="60dip"   android:background="@drawable/button_background_selected"   android:id="@+id/iv_dv_view"  /> <TextView   android:id="@+id/tv_drag_view"   android:layout_marginTop="80dip"   android:layout_width="fill_parent"   android:layout_height="20dip"   android:text="按住绿色条拖动归属地显示的位置"   /></RelativeLayout>