Android事件与手势操作详解

package com.example.myapplication; import android.os.Bundle; import android.view.KeyEvent; import android.widget.Toast; import androidx.appcompat.app.AppCompatActivity; /** * 功能： 连续按两次返回键 退出当前应用 */ public class MainActivity extends AppCompatActivity { private long exitTime = 0; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } @Override public boolean onKeyDown(int keyCode, KeyEvent event) { if(keyCode == KeyEvent.KEYCODE_BACK){ // 执行退出方法, exit(); return true; } return super.onKeyDown(keyCode, event); } public void exit() { if( (System.currentTimeMillis() - exitTime ) > 2000){ Toast.makeText(MainActivity.this, "再按一次退出程序", Toast.LENGTH_SHORT).show(); exitTime = System.currentTimeMillis(); }else{ finish(); System.exit(0); } } }

package com.example.myapplication; import android.os.Bundle; import android.view.MotionEvent; import android.view.View; import android.widget.RelativeLayout; import androidx.appcompat.app.AppCompatActivity; /** * 功能： 通过Touch 移动帽子 给企鹅带帽子 * 1. s实例自顶HatView 在图中 显示帽子位置 * 2. 通过监听OnTouchEvent 不断更新 X,Y 坐标 * 3. 将帽子布局管理器中，动态天剑 */ public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // 添加帽子对象，触摸事件监听器 final HatView hatView = new HatView(MainActivity.this); hatView.setOnTouchListener(new View.OnTouchListener(){ @Override public boolean onTouch(View view, MotionEvent motionEvent) { hatView.bitmapX = motionEvent.getX()- 80; // 减去帽子一般高度，中心点移动 hatView.bitmapY = motionEvent.getY(); // 冲新绘制 hatView.invalidate(); return true; } }); RelativeLayout relativeLayout = findViewById(R.id.relativeLayout); relativeLayout.addView(hatView); } }

package com.example.myapplication; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Paint; import android.view.View; /** *   Hat Postition  通过Touch 方式 移动 * */ public class HatView extends View { public float bitmapX; public float bitmapY; public HatView(Context context) { super(context); this.bitmapX = 0.0f; this.bitmapY = 0.0f; } /** *  重新绘制帽子 * */ @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); Paint paint = new Paint(); Bitmap bitmap = BitmapFactory.decodeResource(this.getResources(), R.drawable.hat); canvas.drawBitmap(bitmap,bitmapX,bitmapY,paint); if(bitmap.isRecycled()){ bitmap.recycle(); } } }

package com.example.myapplication; import android.os.Bundle; import android.view.GestureDetector; import android.view.MotionEvent; import android.view.animation.Animation; import android.view.animation.AnimationUtils; import android.widget.ImageView; import android.widget.ViewFlipper; import androidx.appcompat.app.AppCompatActivity; /** * 手势方式滑动动画 */ public class MainActivity extends AppCompatActivity implements GestureDetector.OnGestureListener { ViewFlipper flipper; //定义ViewFlipper GestureDetector detector; //定义手势检测器 Animation[] animation = new Animation[4];//定义动画数组，为ViewFlipper指定切换动画 final int distance = 50; //定义手势动作两点之间最小距离 //定义图片数组 private int[] images = new int[]{R.drawable.img01, R.drawable.img02, R.drawable.img03, R.drawable.img04, }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); detector = new GestureDetector(MainActivity.this, this); // 将显示的动画加入ViewFlipper 当中，并且初始化动画数组 flipper = findViewById(R.id.flipper); for(int i= 0; i distance){ flipper.setInAnimation(animation[2]); flipper.setAnimation(animation[1]); flipper.showPrevious(); return  true; }else if (e2.getX() - e1.getX() > distance) { //为flipper设置切换的动画 flipper.setInAnimation(animation[0]); flipper.setOutAnimation(animation[3]); flipper.showNext(); return true; } return false; } @Override public boolean onTouchEvent(MotionEvent event) { return detector.onTouchEvent(event); } }

package com.example.myapplication; import android.gesture.Gesture; import android.gesture.GestureLibraries; import android.gesture.GestureLibrary; import android.gesture.GestureOverlayView; import android.gesture.Prediction; import android.graphics.Color; import android.os.Bundle; import android.view.GestureDetector; import android.view.MotionEvent; import android.widget.EditText; import androidx.appcompat.app.AppCompatActivity; import java.util.ArrayList; /** * 手势方式滑动动画 */ public class MainActivity extends AppCompatActivity implements GestureOverlayView.OnGesturePerformedListener { private GestureDetector detector; private GestureLibrary librarry; private EditText editText; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // 加载自定义手势文件， 不成功退出 librarry = GestureLibraries.fromRawResource(MainActivity.this, R.raw.gestures); editText = findViewById(R.id.editText); if(!librarry.load()){ finish(); } // 获取GestureOverlayView 设置其事件监听器 GestureOverlayView gestureOverlayView = findViewById(R.id.gesture); gestureOverlayView.setGestureColor(Color.BLACK); gestureOverlayView.setFadeOffset(1000); gestureOverlayView.addOnGesturePerformedListener(MainActivity.this); } @Override public void onGesturePerformed(GestureOverlayView gestureOverlayView, Gesture gesture) { // 获取其最佳匹配，并更新编辑栏 ArrayList predictions = librarry.recognize(gesture); int index = 0;// 保存当前预测的索引号 double score = 0.0;// 保存当前预测的得分 for (int i = 0; i  score) { index = i; score = result.score; } } String Text = editText.getText().toString(); Text += predictions.get(index).name; editText.setText(Text); } }