Android implements the functions of customizing gestures and recognizing gestures

1. Complete the activity of custom gesture first

1.1 because the gesture file needs to be stored, the permission needs to be declared:

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> //读取SD卡权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> //写入SD卡权限

1.2 simply write a layout file, which uses gestureoverlayview, which is equivalent to a drawing component. There is an important attribute, gesturestroketype. When the value is single, it means that only one stroke is drawn. To draw multiple strokes, the value should be set to multiple:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical"
 tools:context=".addgesture.Main3Activity">
 <Button
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:onClick="recognition"
  android:text="识别手势" />
 <TextView
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:gravity="center"
  android:text="请绘制手势" />
 <android.gesture.GestureOverlayView
  android:id="@+id/activity_main3_gov"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:gesturestrokeType="multiple" //多笔绘制
  ></android.gesture.GestureOverlayView>
</LinearLayout>

1.3 the style of alertdialog is customized here;

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical">
 <LinearLayout
  android:layout_width="match_parent"
  android:layout_height="wrap_content">
  <TextView
   android:layout_width="wrap_content"
   android:layout_height="match_parent"
   android:gravity="center"
   android:text="请输入手势名称" />
  <EditText  //输入手势的名称
   android:id="@+id/save_dialog_et"
   android:layout_width="match_parent"
   android:layout_height="match_parent" />
 </LinearLayout>
 <ImageView  //展示绘制的手势
  android:id="@+id/save_dialog_iv"
  android:layout_width="match_parent"
  android:layout_height="match_parent" />
</LinearLayout>

1.4 code part:

package com.example.mygesture.addgesture;
import android.Manifest;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.gesture.Gesture;
import android.gesture.GestureLibraries;
import android.gesture.GestureLibrary;
import android.gesture.GestureOverlayView;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;
import com.example.mygesture.R;
import com.example.mygesture.recognitiongesture.Main4Activity;
public class Main3Activity extends AppCompatActivity {
 GestureOverlayView gov;   //定义绘制组件
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main3);
  if (ActivityCompat.checkSelfPermission(this,Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
   ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.READ_EXTERNAL_STORAGE,Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
  }    //高版本需要动态申请权限
  init();
 }
 private void init() {
  gov = findViewById(R.id.activity_main3_gov);
//  gov.setGestureColor(Color.RED);  //设置绘制的颜色
  gov.setGesturestrokeWidth(4);  //设置画笔的宽度
  gov.addOnGesturePerformedListener(new GestureOverlayView.OnGesturePerformedListener() { //设置绘制完成监听
   @Override
   public void onGesturePerformed(GestureOverlayView overlay,final Gesture gesture) {
    View saveDialog = getLayoutInflater().inflate(R.layout.save_dialog,null); //获取AlertDialog的布局样式
    final EditText editText = saveDialog.findViewById(R.id.save_dialog_et);
    ImageView imageView = saveDialog.findViewById(R.id.save_dialog_iv);
    Bitmap bitmap = gesture.toBitmap(128,128,10,0xFFFF0000);  //将手势转换为位图
    imageView.setImageBitmap(bitmap);   //用ImageView加载手势图片
    new AlertDialog.Builder(Main3Activity.this).setView(saveDialog).setPositiveButton("确定",new DialogInterface.OnClickListener() {
     @Override
     public void onClick(DialogInterface dialog,int which) {
      GestureLibrary gestureLibrary = GestureLibraries.fromFile("/mnt/sdcard/mygesture");//利用手势库获取存放手势文件的地址
      gestureLibrary.addGesture(editText.getText().toString(),gesture);  //向手势库中添加手势名称和手势
      gestureLibrary.save();    //保存手势库
      Toast.makeText(Main3Activity.this,"保存成功",Toast.LENGTH_SHORT).show();
     }
    }).setNegativeButton("取消",null)
      .show();
   }
  });
 }
 public void recognition(View view) {
  Intent intent = new Intent(this,Main4Activity.class);
  startActivity(intent);
 }
}

2. Next, complete the gesture recognition activity:

2.1 write the layout file first

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical"
 tools:context=".recognitiongesture.Main4Activity">

 <TextView
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:gravity="center"
  android:text="请绘制需要识别的手势" />

 <android.gesture.GestureOverlayView
  android:id="@+id/activity_main4_gov"
  android:layout_width="match_parent"
  android:layout_height="match_parent"></android.gesture.GestureOverlayView>
</LinearLayout>

2.2 code writing

package com.example.mygesture.recognitiongesture;
import android.gesture.Gesture;
import android.gesture.GestureLibraries;
import android.gesture.GestureLibrary;
import android.gesture.GestureOverlayView;
import android.gesture.Prediction;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.Toast;
import com.example.mygesture.R;
import java.util.ArrayList;
import java.util.logging.Level;
public class Main4Activity extends AppCompatActivity {
 GestureOverlayView gov;
 GestureLibrary gestureLibrary;  //定义手势库
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main4);
  init();
 }
 private void init() {
  gestureLibrary = GestureLibraries.fromFile("/mnt/sdcard/mygesture"); //获取手势文件
  if (gestureLibrary.load()) {   //判断手势文件是否存在以及加载
   Toast.makeText(this,"手势文件加载成功",Toast.LENGTH_SHORT).show();
  } else {
   Toast.makeText(this,"手势文件加载失败",Toast.LENGTH_SHORT).show();
  }
  gov = findViewById(R.id.activity_main4_gov);
  gov.addOnGesturePerformedListener(new GestureOverlayView.OnGesturePerformedListener() {
   @Override
   public void onGesturePerformed(GestureOverlayView overlay,Gesture gesture) {
    ArrayList<Prediction> predictions = gestureLibrary.recognize(gesture); //匹配手势库中的所有手势
    ArrayList<String> result = new ArrayList<>();  //匹配结果数组
    for (Prediction pred : predictions) {
     if (pred.score > 2) {    //匹配手势库中的所有手势，并将相似度>2存入匹配结果数组
      result.add("相似度：" + pred.score);
     }
    }
    if (result.size() > 0) {  //这里用了适配器来作为AlertDialog的布局样式，用于显示所有手势的相似度
     ArrayAdapter<Object> arrayAdapter = new ArrayAdapter<Object>(Main4Activity.this,android.R.layout.simple_dropdown_item_1line,result.toArray());
     new AlertDialog.Builder(Main4Activity.this).setAdapter(arrayAdapter,null).setPositiveButton("确定",null).show();
    } else {
     Toast.makeText(Main4Activity.this,"未找到与之匹配的手势",Toast.LENGTH_SHORT).show();
    }
   }
  });
 }
}

summary

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