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Android開發(fā)中實(shí)現(xiàn)多點(diǎn)觸摸的方法
我們曾就《Android手勢識別ViewFlipper觸摸動畫》做過詳細(xì)的講解，其實(shí)，Android應(yīng)用程序開發(fā)中，多點(diǎn)觸摸（Multitouch）不是那么遙不可及，實(shí)現(xiàn)起來也很簡單。如果您對開發(fā)多點(diǎn)觸摸程序感興趣的話，那么本文將是一個很好的開始，本例只需要兩個類就能實(shí)現(xiàn)多點(diǎn)觸摸。
鹽亭網(wǎng)站制作公司哪家好，找創(chuàng)新互聯(lián)！從網(wǎng)頁設(shè)計(jì)、網(wǎng)站建設(shè)、微信開發(fā)、APP開發(fā)、成都響應(yīng)式網(wǎng)站建設(shè)公司等網(wǎng)站項(xiàng)目制作，到程序開發(fā)，運(yùn)營維護(hù)。創(chuàng)新互聯(lián)于2013年成立到現(xiàn)在10年的時間，我們擁有了豐富的建站經(jīng)驗(yàn)和運(yùn)維經(jīng)驗(yàn)，來保證我們的工作的順利進(jìn)行。專注于網(wǎng)站建設(shè)就選創(chuàng)新互聯(lián)。
首先來看看我們的視圖類MTView.java:
- package com.ideasandroid.demo;
- import android.content.Context;
- import android.graphics.Canvas;
- import android.graphics.Color;
- import android.graphics.Paint;
- import android.view.MotionEvent;
- import android.view.SurfaceHolder;
- import android.view.SurfaceView;
- public class MTView extends SurfaceView implements SurfaceHolder.Callback {
- private static final int MAX_TOUCHPOINTS = 10;
- private static final String START_TEXT = "請隨便觸摸屏幕進(jìn)行測試";
- private Paint textPaint = new Paint();
- private Paint touchPaints[] = new Paint[MAX_TOUCHPOINTS];
- private int colors[] = new int[MAX_TOUCHPOINTS];
- private int width, height;
- private float scale = 1.0f;
- public MTView(Context context) {
- super(context);
- SurfaceHolder holder = getHolder();
- holder.addCallback(this);
- setFocusable(true); // 確保我們的View能獲得輸入焦點(diǎn)
- setFocusableInTouchMode(true); // 確保能接收到觸屏事件
- init();
- }
- private void init() {
- // 初始化10個不同顏色的畫筆
- textPaint.setColor(Color.WHITE);
- colors[0] = Color.BLUE;
- colors[1] = Color.RED;
- colors[2] = Color.GREEN;
- colors[3] = Color.YELLOW;
- colors[4] = Color.CYAN;
- colors[5] = Color.MAGENTA;
- colors[6] = Color.DKGRAY;
- colors[7] = Color.WHITE;
- colors[8] = Color.LTGRAY;
- colors[9] = Color.GRAY;
- for (int i = 0; i < MAX_TOUCHPOINTS; i++) {
- touchPaints[i] = new Paint();
- touchPaints[i].setColor(colors[i]);
- }
- }
- /*
- * 處理觸屏事件
- */
- @Override
- public boolean onTouchEvent(MotionEvent event) {
- // 獲得屏幕觸點(diǎn)數(shù)量
- int pointerCount = event.getPointerCount();
- if (pointerCount > MAX_TOUCHPOINTS) {
- pointerCount = MAX_TOUCHPOINTS;
- }
- // 鎖定Canvas,開始進(jìn)行相應(yīng)的界面處理
- Canvas c = getHolder().lockCanvas();
- if (c != null) {
- c.drawColor(Color.BLACK);
- if (event.getAction() == MotionEvent.ACTION_UP) {
- // 當(dāng)手離開屏幕時，清屏
- } else {
- // 先在屏幕上畫一個十字，然后畫一個圓
- for (int i = 0; i < pointerCount; i++) {
- // 獲取一個觸點(diǎn)的坐標(biāo)，然后開始繪制
- int id = event.getPointerId(i);
- int x = (int) event.getX(i);
- int y = (int) event.getY(i);
- drawCrosshairsAndText(x, y, touchPaints[id], i, id, c);
- }
- for (int i = 0; i < pointerCount; i++) {
- int id = event.getPointerId(i);
- int x = (int) event.getX(i);
- int y = (int) event.getY(i);
- drawCircle(x, y, touchPaints[id], c);
- }
- }
- // 畫完后，unlock
- getHolder().unlockCanvasAndPost(c);
- }
- return true;
- }
- /**
- * 畫十字及坐標(biāo)信息
- *
- * @param x
- * @param y
- * @param paint
- * @param ptr
- * @param id
- * @param c
- */
- private void drawCrosshairsAndText(int x, int y, Paint paint, int ptr,
- int id, Canvas c) {
- c.drawLine(0, y, width, y, paint);
- c.drawLine(x, 0, x, height, paint);
- int textY = (int) ((15 + 20 * ptr) * scale);
- c.drawText("x" + ptr + "=" + x, 10 * scale, textY, textPaint);
- c.drawText("y" + ptr + "=" + y, 70 * scale, textY, textPaint);
- c.drawText("id" + ptr + "=" + id, width - 55 * scale, textY, textPaint);
- }
- /**
- * 畫圓
- *
- * @param x
- * @param y
- * @param paint
- * @param c
- */
- private void drawCircle(int x, int y, Paint paint, Canvas c) {
- c.drawCircle(x, y, 40 * scale, paint);
- }
- /*
- * 進(jìn)入程序時背景畫成黑色，然后把“START_TEXT”寫到屏幕
- */
- public void surfaceChanged(SurfaceHolder holder, int format, intwidth,
- int height) {
- this.width = width;
- this.height = height;
- if (width > height) {
- this.scale = width / 480f;
- } else {
- this.scale = height / 480f;
- }
- textPaint.setTextSize(14 * scale);
- Canvas c = getHolder().lockCanvas();
- if (c != null) {
- // 背景黑色
- c.drawColor(Color.BLACK);
- float tWidth = textPaint.measureText(START_TEXT);
- c.drawText(START_TEXT, width / 2 - tWidth / 2, height / 2,
- textPaint);
- getHolder().unlockCanvasAndPost(c);
- }
- }
- public void surfaceCreated(SurfaceHolder holder) {
- }
- public void surfaceDestroyed(SurfaceHolder holder) {
- }
- }
接下來看看我們的Activity，MultitouchVisible.java
- package com.ideasandroid.demo;
- import android.app.Activity;
- import android.os.Bundle;
- import android.view.Window;
- import android.view.WindowManager;
- public class MultitouchVisible extends Activity {
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- //隱藏標(biāo)題欄
- requestWindowFeature(Window.FEATURE_NO_TITLE);
- //設(shè)置成全屏
- getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
- WindowManager.LayoutParams.FLAG_FULLSCREEN);
- //設(shè)置為上面的MTView
- setContentView(new MTView(this));
- }
- }
希望本文對您有所幫助。
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