Custom Controls --- inherit the View class (colorful water ripple case), view water ripple

Custom Controls --- inherit the View class (colorful water ripple case), view water ripple

--------------------------------------- View the effect (and animation effect )----------------------------------------------------

Activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent" >    <com.atguigu.myware.MyWave        android:layout_width="match_parent"        android:layout_height="match_parent" /></RelativeLayout>

MainActivity. java

package com.atguigu.myware;import android.os.Bundle;import android.app.Activity;import android.view.Menu;public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}}

MyWave. java

Package com. atguigu. myware; import java. util. arrayList; import android. content. context; import android. graphics. canvas; import android. graphics. color; import android. graphics. paint; import android. graphics. paint. style; import android. OS. handler; import android. util. attributeSet; import android. view. motionEvent; import android. view. view;/*** water ripple effect */public class MyWave extends View {/*** defines a water ripple class (a circle includes a circle center, radius, and paint brush (to be drawn )) */private class Wave {// center int pointX; int pointY; // radius int radius; // Paint paint ;} // The minimum distance between the two adjacent wave centers is private static final int DIS_SOLP = 13; // whether there is water wave protected boolean isRunning = false; /*** Step 1 constructor * // defines the set of Water ripple private ArrayList <Wave> wList; public MyWave (Context context, AttributeSet attrs) {super (context, attrs ); // initialize and create a ripple collection wList = new ArrayList <MyWave. wave> ();}/*** touch event */@ Overridepublic boolean onTouchEvent (MotionEvent event) {super. onTouchEvent (event); switch (event. getAction () {// press the screen and slide to generate a water wave case MotionEvent. ACTION_DOWN: case MotionEvent. ACTION_MOVE: // get the int x = (int) event of the Center of down and move. getX (); int y = (int) event. getY (); // if the water ripple set is empty, draw a water ripple if (wList. size () = 0) {// draw the water ripple addPoint2List (x, y); // modify the status, indicating that the water wave generates isRunning = true; // send a message at the moment, it indicates that a water wave handler is drawn. sendEmptyMessage (0);} else {// if the water Wave set is not empty, go to the last drawn ring water Wave w = wList. get (wList. size ()-1); if (Math. abs (w. pointX-x)> DIS_SOLP | Math. abs (w. pointY-y)> DIS_SOLP) {addPoint2List (x, y) ;}; break; default: break;} return true ;} /** define four colors of water waves */private int [] colors = new int [] {Color. BLUE, Color. RED, Color. YELLOW, Color. GREEN};/*** Add a Wave */private void addPoint2List (int x, int y) {// create a water Wave w = new Wave (); // assign the coordinates of sliding or pressing to the water wave class w. pointX = x; w. pointY = y; // create a Paint brush Paint pa = new Paint (); // draw a water wave (ring) to set the color, anti-tooth, shape pa. setColor (colors [(int) (Math. random () * 4)]); pa. setAntiAlias (true); pa. setStyle (Style. STROKE); // assign a value to w. paint = pa; // Add a circular water wList to the set. add (w);}/*** draw water ripple */@ Overrideprotected void onDraw (Canvas canvas) {for (int I = 0; I <wList. size (); I ++) {Wave wave = wList. get (I); canvas. drawCircle (wave. pointX, wave. pointY, wave. radius, wave. paint) ;}}/** use message mechanism */private Handler handler = new Handler () {public void handleMessage (android. OS. message msg) {// receives the sent Message for the corresponding operation // refresh the data flushData (); // refresh the page invalidate (); // cyclically animated if (isRunning) {handler. sendEmptyMessageDelayed (0, 50) ;};};/*** refresh data (operate on the transparency and radius of the annular water wave) */private void flushData () {for (int I = 0; I <wList. size (); I ++) {Wave w = wList. get (I); // If the transparency is 0, delete int alpha = w from the set. paint. getAlpha (); if (alpha = 0) {wList. remove (I); continue;} // opacity values minus 5 alpha-= 5 each time; if (alpha <5) {alpha = 0 ;}// opacity reduction w. paint. setAlpha (alpha); // expand the radius w. radius = w. radius + 3; // set the radius thickness w. paint. setStrokeWidth (w. radius/3);}/** if the set is cleared, stop refreshing the animation */if (wList. size () = 0) {isRunning = false ;}}}

--------------------------- View a simple version ---------------------- the effect is gradually increased until it disappears --------------------------------

Activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent" >    <com.atguigu.myware.MyWave        android:layout_width="match_parent"        android:layout_height="match_parent" /></RelativeLayout>

MainActivity. java

package com.atguigu.myware;import android.os.Bundle;import android.app.Activity;import android.view.Menu;public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}}

MyWave. java

Package com. atguigu. myware; import android. content. context; import android. graphics. canvas; import android. graphics. color; import android. graphics. paint; import android. graphics. paint. style; import android. OS. handler; import android. util. attributeSet; import android. view. motionEvent; import android. view. view;/*** watermark effect View **/public class MyWave extends View {private Paint paint; @ Overridepublic boolean on TouchEvent (MotionEvent event) {super. onTouchEvent (event); switch (event. getAction () {/** start to draw the Ring Water ripple when pressing */case MotionEvent. ACTION_DOWN: // 1. set startX = event. getX (); startY = event. getY (); // 2. create a new initView () based on the center of the circle; // 3. draw invalidate (); break; default: break;} return true;} private Handler handler = new Handler () {public void handleMessage (android. OS. message msg) {// 1. transparency changed-small int alpha = paint. getAlpha (); Alpha-= 5; if (alpha <0) {alpha = 0;} // transparency: 0 ~ Between 255 paint. setAlpha (alpha); // 2. larger radius: radius + = 5; paint. setStrokeWidth (radius/3); // 3. draw one more and execute the onDraw method invalidate () ;};/ ** step 1, constructor */public MyWave (Context context, AttributeSet attrs) {super (context, attrs); initView ();}/*** initialize View */private int radius; // radius private void initView () {paint = new Paint (); // set the color to paint. setColor (Color. RED); // set the anti-sawtooth paint. setAntiAlias (true); // set the ring style paint. setStyle (Style. STROKE); // The radius is 5 radius = 5; paint. setStrokeWidth (radius/3);} // circular coordinate private float startX; private float startY;/*** draw circular water ripple */@ Overrideprotected void onDraw (Canvas canvas Canvas) {if (paint. getAlpha ()> 0) {if (startX> 0 & startY> 0) {// draw a circle canvas. drawCircle (startX, startY, radius, paint); // send a delayed message handler while plotting. sendEmptyMessageDelayed (0, 50 );}}}}