Android Custom LineLayout Realization Full Screen Arbitrary Drag Function Sample Code

1. Preface

In the development, there will be requirements to achieve controls in the screen dragging at will, which requires custom View, and then in OnTouchEvent event, processing MotionEvent.ACTION_MOVE event, and then through the coordinate point value to onlayout method, to achieve arbitrary control dragging, the specific code is as follows:

import android.content.Context;
import android.util.AttributeSet;
import android.view.Display;
import android.view.MotionEvent;
import android.view.WindowManager;
import android.widget.LinearLayout;

public class DragLineLayout extends LinearLayout {

 private int mWidth;
 private int mHeight;
 private int mScreenWidth;
 private int mScreenHeight;
 private Context mContext;
 private onLocationListener mLocationListener;/*listen to the Rect */
 // Drag or not 
 private boolean isDrag = false;

 public boolean isDrag() {
  return isDrag;
 }

 public DragView(Context context, AttributeSet attrs) {
  super(context, attrs);
  this.mContext = context;
 }

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  super.onMeasure(widthMeasureSpec, heightMeasureSpec);
  mWidth = getMeasuredWidth();
  mHeight = getMeasuredHeight();
  mScreenWidth = getScreenWidth(mContext);
  mScreenHeight = getScreenHeight(mContext) - getStatusBarHeight();
 }

 public int getStatusBarHeight() {
  int resourceId = mContext.getResources().getIdentifier("status_bar_height", "dimen", "android");
  return mContext.getResources().getDimensionPixelSize(resourceId);
 }

 public int getScreenWidth(Context context) {
  WindowManager manager = (WindowManager) context
    .getSystemService(Context.WINDOW_SERVICE);
  Display display = manager.getDefaultDisplay();
  return display.getWidth();
 }

 public int getScreenHeight(Context context) {
  WindowManager manager = (WindowManager) context
    .getSystemService(Context.WINDOW_SERVICE);
  Display display = manager.getDefaultDisplay();
  return display.getHeight();
 }

 private float mDownX;
 private float mDownY;


 @Override
 public boolean onTouchEvent(MotionEvent event) {
  super.onTouchEvent(event);
  if (this.isEnabled()) {
   switch (event.getAction()) {
    case MotionEvent.ACTION_DOWN:
     isDrag = false;
     mDownX = event.getX();
     mDownY = event.getY();
     break;
    case MotionEvent.ACTION_MOVE:
     final float mXdistance = event.getX() - mDownX;
     final float mYdistance = event.getY() - mDownY;
     int l, r, t, b;
     // When the horizontal or vertical sliding distance is greater than 10, Is considered a drag event 
     if (Math.abs(mXdistance) > 10 || Math.abs(mYdistance) > 10) {
      isDrag = true;
      l = (int) (getLeft() + mXdistance);
      r = l + mWidth;
      t = (int) (getTop() + mYdistance);
      b = t + mHeight;
      // Boundary judgment , Don't let the layout slip out of the interface 
      if (l < 0) {
       l = 0;
       r = l + mWidth;
      } else if (r > mScreenWidth) {
       r = mScreenWidth;
       l = r - mWidth;
      }
      if (t < 0) {
       t = 0;
       b = t + mHeight;
      } else if (b > mScreenHeight) {
       b = mScreenHeight;
       t = b - mHeight;
      }
      // Callback moved coordinate point 
      if(mLocationListener!=null){
       mLocationListener.locationRect((l+r)/2,(t+b)/2);
      }
      this.layout(l, t, r, b);
     }
     break;
    case MotionEvent.ACTION_UP:
     setPressed(false);
     break;
    case MotionEvent.ACTION_CANCEL:
     setPressed(false);
     break;
   }
   return true;
  }
  return false;
 }
 public void setLocationListener(onLocationListener LocationListener) {
  this.mLocationListener = LocationListener;
 }
 public interface onLocationListener {
  void locationRect(float locationX, float locationY);
 }
}

2. Use in code

<com.xinrui.guestservice.view.DragLineLayout 
 xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="@dimen/dp_200"
 android:layout_height="@dimen/dp_110"
 android:orientation="vertical">
 <RelativeLayout
  android:layout_width="match_parent"
  android:layout_height="@dimen/dp_50">
 <EditText
  android:id="@+id/input_edt"
  android:layout_width="match_parent"
  android:layout_height="@dimen/dp_50"
  android:background="@drawable/edit_bg" />
 </RelativeLayout>
 <RelativeLayout
  android:layout_width="match_parent"
  android:layout_height="@dimen/dp_55"
  android:layout_marginTop="@dimen/margin_5"
  android:background="@drawable/paint_bg">

  <TextView
   android:id="@+id/paint_typeface"
   android:layout_width="@dimen/dp_50"
   android:layout_height="@dimen/dp_50"
   android:layout_alignParentLeft="true"
   android:layout_alignParentTop="true"
   android:layout_marginTop="@dimen/margin_5"
   android:background="@drawable/main_selector_write"
   android:clickable="true" />

  <TextView
   android:id="@+id/paint_fontsize"
   android:layout_width="@dimen/dp_50"
   android:layout_height="@dimen/dp_50"
   android:layout_alignParentTop="true"
   android:layout_marginLeft="@dimen/dp_10"
   android:layout_marginTop="@dimen/margin_5"
   android:layout_toRightOf="@id/paint_typeface"
   android:background="@drawable/main_selector_write"
   android:clickable="true" />
 </RelativeLayout>
</com.xinrui.guestservice.view.DragLineLayout>

3. This allows you to load the xml on the Activity for any drag function

Summarize