1.android 触摸事件侦听
安卓的用户交互方式包括两种，一种是点击交互，一种是触摸交互。点击交互就是手指按下抬起一个动作组。而触摸交互分为按下（down），移动（move），抬起（up）。
触摸事件侦听代码：输出触摸事件的三个动作：
我们用一个framlayout布局进行操作
import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.MotionEvent;import android.view.View;import android.widget.FrameLayout;public class MainActivity extends AppCompatActivity { private FrameLayout container; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); container = (FrameLayout) findViewById(R.id.container); container.setOnTouchListener(new View.OnTouchListener() { @Override public boolean onTouch(View view, MotionEvent motionEvent) { switch (motionEvent.getAction()){ case MotionEvent.ACTION_DOWN: System.out.println("action:down"); break; case MotionEvent.ACTION_MOVE: System.out.println("action:move"); break; case MotionEvent.ACTION_UP: System.out.println("action:up"); break; } return true; //remember to change this return to ture } }); }} 注意：记得把onTouch方法的返回值改成true。
运行结果：
07-13 14:35:19.883 11720-11720/bhu.com.myapplication I/System.out: action:down07-13 14:35:19.924 11720-11720/bhu.com.myapplication I/System.out: action:move07-13 14:35:19.954 11720-11720/bhu.com.myapplication I/System.out: action:move07-13 14:35:19.964 11720-11720/bhu.com.myapplication I/System.out: action:move07-13 14:35:19.984 11720-11720/bhu.com.myapplication I/System.out: action:move07-13 14:35:19.984 11720-11720/bhu.com.myapplication I/System.out: action:up
2.获取触摸的当前坐标
import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.MotionEvent;import android.view.View;import android.widget.FrameLayout;public class MainActivity extends AppCompatActivity { private FrameLayout container; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); container = (FrameLayout) findViewById(R.id.container); container.setOnTouchListener(new View.OnTouchListener() { @Override public boolean onTouch(View view, MotionEvent motionEvent) { switch (motionEvent.getAction()){ case MotionEvent.ACTION_DOWN: System.out.println("action:down"); break; case MotionEvent.ACTION_MOVE: System.out.println(String.format("(%f,%f)",motionEvent.getX(),motionEvent.getY())); break; case MotionEvent.ACTION_UP: System.out.println("action:up"); break; } return true; //remember to change this return to ture } }); }} 输出结果：
07-13 14:39:50.442 11720-11720/bhu.com.myapplication I/System.out: (366.251312,682.000000)07-13 14:39:50.452 11720-11720/bhu.com.myapplication I/System.out: (367.076874,682.000000)07-13 14:39:50.472 11720-11720/bhu.com.myapplication I/System.out: (367.000000,680.500000)07-13 14:39:50.482 11720-11720/bhu.com.myapplication I/System.out: (368.067780,681.000000)07-13 14:39:50.512 11720-11720/bhu.com.myapplication I/System.out: (369.000000,681.000000)07-13 14:39:50.532 11720-11720/bhu.com.myapplication I/System.out: (370.142609,681.000000)07-13 14:39:50.542 11720-11720/bhu.com.myapplication I/System.out: (371.500000,681.000000)07-13 14:39:50.582 11720-11720/bhu.com.myapplication I/System.out: (373.497681,681.000000)07-13 14:39:50.592 11720-11720/bhu.com.myapplication I/System.out: (374.960114,681.000000)07-13 14:39:50.612 11720-11720/bhu.com.myapplication I/System.out: (376.413116,681.000000)
3.实现拖动控件
import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.MotionEvent;import android.view.View;import android.widget.FrameLayout;import android.widget.ImageView;public class MainActivity extends AppCompatActivity { private FrameLayout container; private ImageView imv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); container = (FrameLayout) findViewById(R.id.container); imv = (ImageView) findViewById(R.id.imv); container.setOnTouchListener(new View.OnTouchListener() { @Override public boolean onTouch(View view, MotionEvent motionEvent) { switch (motionEvent.getAction()){ case MotionEvent.ACTION_DOWN: System.out.println("action:down"); break; case MotionEvent.ACTION_MOVE: //System.out.println(String.format("(%f,%f)",motionEvent.getX(),motionEvent.getY())); FrameLayout.LayoutParams lp = (FrameLayout.LayoutParams) imv.getLayoutParams(); lp.leftMargin = (int) motionEvent.getX(); lp.topMargin = (int) motionEvent.getY(); imv.setLayoutParams(lp); break; case MotionEvent.ACTION_UP: System.out.println("action:up"); break; } return true; //remember to change this return to ture } }); }} 运行结果：
该图片无法显示！
4.获取多个触控点的坐标
import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.MotionEvent;import android.view.View;import android.widget.FrameLayout;import android.widget.ImageView;public class MainActivity extends AppCompatActivity { private FrameLayout container; private ImageView imv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); container = (FrameLayout) findViewById(R.id.container); imv = (ImageView) findViewById(R.id.imv); container.setOnTouchListener(new View.OnTouchListener() { @Override public boolean onTouch(View view, MotionEvent motionEvent) { switch (motionEvent.getAction()){ case MotionEvent.ACTION_DOWN: System.out.println("action:down"); break; case MotionEvent.ACTION_MOVE: //System.out.println(String.format("(%f,%f)",motionEvent.getX(),motionEvent.getY())); System.out.println("pointers count:"+motionEvent.getPointerCount()); //get the number of pointers System.out.println(String.format("point1:(%f,%f) point2:(%f,%f)",motionEvent.getX(0),motionEvent.getY(0),motionEvent.getX(1),motionEvent.getY(1))); //when you put just one finger on the screen,there will be a exception,because there is not a getX(1). break; case MotionEvent.ACTION_UP: System.out.println("action:up"); break; } return true; //remember to change this return to ture } }); } 输出结果：
07-13 14:54:52.855 5804-5804/bhu.com.myapplication I/System.out: point1:(245.296295,718.407410) point2:(456.000000,389.000000)07-13 14:54:52.865 5804-5804/bhu.com.myapplication I/System.out: pointers count:207-13 14:54:52.865 5804-5804/bhu.com.myapplication I/System.out: point1:(244.000000,721.000000) point2:(455.000000,392.000000)07-13 14:54:52.885 5804-5804/bhu.com.myapplication I/System.out: pointers count:207-13 14:54:52.885 5804-5804/bhu.com.myapplication I/System.out: point1:(242.387100,722.612915) point2:(454.000000,394.000000)07-13 14:54:52.895 5804-5804/bhu.com.myapplication I/System.out: pointers count:207-13 14:54:52.905 5804-5804/bhu.com.myapplication I/System.out: point1:(242.000000,724.000000) point2:(453.000000,396.000000)07-13 14:54:52.915 5804-5804/bhu.com.myapplication I/System.out: pointers count:207-13 14:54:52.915 5804-5804/bhu.com.myapplication I/System.out: point1:(241.000000,724.000000) point2:(452.000000,397.000000)07-13 14:54:52.935 5804-5804/bhu.com.myapplication I/System.out: pointers count:207-13 14:54:52.935 5804-5804/bhu.com.myapplication I/System.out: point1:(241.000000,725.000000) point2:(452.000000,397.000000)
5.根据手势动作实现图片的缩放（两点触控）<并且可以拖动>
import android.net.Uri;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.MotionEvent;import android.view.View;import android.widget.FrameLayout;import android.widget.ImageView;import com.google.android.gms.appindexing.Action;import com.google.android.gms.appindexing.AppIndex;import com.google.android.gms.common.api.GoogleApiClient;public class MainActivity extends AppCompatActivity { private FrameLayout container; private ImageView imv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); container = (FrameLayout) findViewById(R.id.container); imv = (ImageView) findViewById(R.id.imv); container.setOnTouchListener(new View.OnTouchListener() { float cureentDistance; float lastDistance = -1; //the distance of two point can not be a minus,when the distance is -1 ,it means it's a initial value. @Override public boolean onTouch(View view, MotionEvent motionEvent) { switch (motionEvent.getAction()) { case MotionEvent.ACTION_DOWN: System.out.println("action:down"); break; case MotionEvent.ACTION_MOVE: if (motionEvent.getPointerCount() >= 2) { //there must be two finger on the screen float offsetX = motionEvent.getX(0) - motionEvent.getX(1); float offsetY = motionEvent.getY(1) - motionEvent.getY(1); cureentDistance = (float) Math.sqrt(offsetX * offsetX + offsetY * offsetY); if (lastDistance < 0) { lastDistance = cureentDistance; } else { if (cureentDistance - lastDistance > 5) { System.out.println("Zoom in"); FrameLayout.LayoutParams lp = (FrameLayout.LayoutParams) imv.getLayoutParams(); lp.width = (int) (1.1f*imv.getWidth()); lp.height = (int) (1.1f*imv.getHeight()); imv.setLayoutParams(lp); lastDistance = cureentDistance; } else if (lastDistance - cureentDistance > 5) { System.out.println("Zoom out"); FrameLayout.LayoutParams lp = (FrameLayout.LayoutParams) imv.getLayoutParams(); lp.width = (int) (0.9f*imv.getWidth()); lp.height = (int) (0.9f*imv.getHeight()); imv.setLayoutParams(lp); lastDistance = cureentDistance; } } }else{ FrameLayout.LayoutParams lp = (FrameLayout.LayoutParams) imv.getLayoutParams(); lp.leftMargin = (int) (motionEvent.getX()-(imv.getWidth()/2)); lp.topMargin = (int) (motionEvent.getY()-(imv.getHeight()/2)); imv.setLayoutParams(lp); } break; case MotionEvent.ACTION_UP: System.out.println("action:up"); break; } return true; //remember to change this return to ture } }); } }