Android Realizes random drag View effect example code
- 2021-11-10 11:01:27
- OfStack
In the process of the project, you should be able to drag at will in the page. At the beginning, it was realized in the form of a suspended ball. Because it has been used in previous projects, it is found that users have permission restrictions after each installation, and even some users don't know how to open the permission of floating ball on their mobile phones after closing the permission of floating ball. In this way, the user experience is very bad, so they re-define the implementation and drag it in the page without requesting permission.
Custom drag View at will:
package com.dragdemo;
import android.annotation.SuppressLint;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.ImageView;
/**
* Drag at will view
*/
@SuppressLint("AppCompatCustomView")
public class DragView extends ImageView {
private int width;
private int height;
private int screenWidth;
private int screenHeight;
private Context context;
// Drag or not
private boolean isDrag=false;
public boolean isDrag() {
return isDrag;
}
public DragView(Context context, AttributeSet attrs) {
super(context, attrs);
this.context=context;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
width=getMeasuredWidth();
height=getMeasuredHeight();
screenWidth= ScreenUtil.getScreenWidth(context);
screenHeight=ScreenUtil.getScreenHeight(context)-getStatusBarHeight();
}
public int getStatusBarHeight(){
int resourceId = getResources().getIdentifier("status_bar_height", "dimen", "android");
return getResources().getDimensionPixelSize(resourceId);
}
private float downX;
private float downY;
@Override
public boolean onTouchEvent(MotionEvent event) {
super.onTouchEvent(event);
if (this.isEnabled()) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
isDrag=false;
downX = event.getX();
downY = event.getY();
break;
case MotionEvent.ACTION_MOVE:
Log.e("kid","ACTION_MOVE");
final float xDistance = event.getX() - downX;
final float yDistance = event.getY() - downY;
int l,r,t,b;
// When the horizontal or vertical sliding distance is greater than 10, To count as a drag event
if (Math.abs(xDistance) >10 ||Math.abs(yDistance)>10) {
Log.e("kid","Drag");
isDrag=true;
l = (int) (getLeft() + xDistance);
r = l+width;
t = (int) (getTop() + yDistance);
b = t+height;
// Judgment without drawing boundaries , Here should be in accordance with the actual situation of the project , Because the moving position of this project is the full screen of the mobile phone ,
// That's why I can write it like this , If it is a fixed area , To get the width and height position of the parent control before processing
if(l<0){
l=0;
r=l+width;
}else if(r>screenWidth){
r=screenWidth;
l=r-width;
}
if(t<0){
t=0;
b=t+height;
}else if(b>screenHeight){
b=screenHeight;
t=b-height;
}
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;
}
}Utility classes used:
package com.dragdemo;
import android.content.Context;
import android.util.DisplayMetrics;
import android.view.Display;
import android.view.View;
import android.view.WindowManager;
public class ScreenUtil {
private static int width = 0;
private static int height = 0;
private static int showHeight = 0;
private static int statusHeight = 0;
private static float density = 0;
public static int getScreenWidth(Context context) {
if (width == 0) {
WindowManager manager = (WindowManager) context
.getSystemService(Context.WINDOW_SERVICE);
Display display = manager.getDefaultDisplay();
width = display.getWidth();
}
return width;
}
public static int getScreenHeight(Context context) {
if (height == 0) {
WindowManager manager = (WindowManager) context
.getSystemService(Context.WINDOW_SERVICE);
Display display = manager.getDefaultDisplay();
height = display.getHeight();
}
return height;
}
public static int getScreenShowHeight(Context context) {
if (showHeight == 0) {
showHeight = getScreenHeight(context) - getStatusBarHeight(context);
}
return showHeight;
}
public static int getStatusBarHeight(Context context) {
if (statusHeight > 0) {
return statusHeight;
}
Class<?> c = null;
Object obj = null;
java.lang.reflect.Field field = null;
int x = 0;
try {
c = Class.forName("com.android.internal.R$dimen");
obj = c.newInstance();
field = c.getField("status_bar_height");
x = Integer.parseInt(field.get(obj).toString());
statusHeight = context.getResources().getDimensionPixelSize(x);
return statusHeight;
} catch (Throwable e) {
e.printStackTrace();
}
return statusHeight;
}
public static float getScreenDensity(Context context) {
if (density == 0) {
try {
DisplayMetrics dm = new DisplayMetrics();
WindowManager manager = (WindowManager) context
.getSystemService(Context.WINDOW_SERVICE);
manager.getDefaultDisplay().getMetrics(dm);
density = dm.density;
} catch (Exception ex) {
ex.printStackTrace();
density = 1.0f;
}
}
return density;
}
public static float getScreentMinLength(Context context) {
return getScreenHeight(context) > getScreenWidth(context) ? getScreenWidth(context)
: getScreenHeight(context);
}
/**
* According to the designation k The coefficient acquisition screen of the max Maximum length and width within the range , The default width ratio is small
*
* @param context
* @param k
* @return
*/
public static DrawWrap getCutWrap(Context context, float k, float max) {
float tWidth = getScreenWidth(context);
float tHeight = getScreenHeight(context);
if (tWidth * max * k > tHeight) {
return new DrawWrap(tHeight * max / k, tHeight * max);
} else {
return new DrawWrap(tWidth * max, tWidth * max * k);
}
}
public static class DrawWrap {
public float width;
public float height;
public DrawWrap(float width, float height) {
this.width = width;
this.height = height;
}
}
public static int dip2px(Context context, float dipValue) {
return (int) (dipValue * getScreenDensity(context) + 0.5f);
}
/**
* Will sp Value is converted to px Value to ensure that the text size is unchanged
*
* @param context
* @param spValue
* ( DisplayMetrics Attributes in class scaledDensity )
* @return
*/
public static int sp2px(Context context, float spValue) {
final float fontScale = context.getResources().getDisplayMetrics().scaledDensity;
return (int) (spValue * fontScale + 0.5f);
}
/**
* According to the resolution of the mobile phone from px( Pixel ) Unit of Turn into dp
*/
public static int px2dip(Context context, float pxValue) {
final float scale = context.getResources().getDisplayMetrics().density;
return (int) (pxValue / scale + 0.5f);
}
/**
* Gets the height of the top position of the control on the screen -- That is, the at the top of the control Y Point
*
* @return
*/
public static int getScreenViewTopHeight(View view) {
return view.getTop();
}
/**
* Gets the height of the bottom position of the control in the screen -- That is, the at the bottom of the control Y Point
*
* @return
*/
public static int getScreenViewBottomHeight(View view) {
return view.getBottom();
}
/**
* Gets the position on the left side of the control in the screen -- That is, the left side of the control X Point
*
* @return
*/
public static int getScreenViewLeftHeight(View view) {
return view.getLeft();
}
/**
* Gets the position on the right side of the control on the screen -- That is, the right side of the control X Point
*
* @return
*/
public static int getScreenViewRightHeight(View view) {
return view.getRight();
}
/*
* Gets the width of the control
*/
public static int getWidth(View view) {
int w = View.MeasureSpec.makeMeasureSpec(0,
View.MeasureSpec.UNSPECIFIED);
int h = View.MeasureSpec.makeMeasureSpec(0,
View.MeasureSpec.UNSPECIFIED);
view.measure(w, h);
return (view.getMeasuredWidth());
}
/*
* Gets control height
*/
public static int getHeight(View view) {
int w = View.MeasureSpec.makeMeasureSpec(0,
View.MeasureSpec.UNSPECIFIED);
int h = View.MeasureSpec.makeMeasureSpec(0,
View.MeasureSpec.UNSPECIFIED);
view.measure(w, h);
return (view.getMeasuredHeight());
}
}XML file:
<com.dragdemo.DragView
android:id="@+id/iv_drag"
android:layout_gravity="center"
android:src="@drawable/function_night_open"
android:layout_width="80dp"
android:layout_height="80dp"
/>MainActivity:
package com.dragdemo;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
DragView iv_drag;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
iv_drag= (DragView) findViewById(R.id.iv_drag);
iv_drag.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(!iv_drag.isDrag()){
Toast.makeText(MainActivity.this, " Response click ", Toast.LENGTH_SHORT).show();
}
}
});
}
}Summarize