EffectDemo/app/src/main/java/com/xunao/effectdemo/activity/DragActivity.java

package com.xunao.effectdemo.activity;

import static com.blankj.utilcode.util.ScreenUtils.getScreenHeight;
import static com.blankj.utilcode.util.ScreenUtils.getScreenWidth;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.res.ResourcesCompat;

import android.animation.Animator;
import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
import android.app.Activity;
import android.content.ClipData;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.os.Bundle;
import android.os.SystemClock;
import android.util.Log;
import android.util.TypedValue;
import android.view.DragEvent;
import android.view.Gravity;
import android.view.HapticFeedbackConstants;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.view.animation.TranslateAnimation;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;

import com.xunao.effectdemo.R;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.Timer;
import java.util.TimerTask;

public class DragActivity extends Activity{

    private static final String RED = "RED";

    RelativeLayout select_rl;
    RelativeLayout rl_bg;
    TextView tv_content;

    //进行滑动的TextView
    private TextView moveTextView;
    List<String> selectList;
    private int answerSize = 0;
    private int halfAnswerSize = 0;
    private int selectRootWidth = 0;
    private int selectRootHeight = 0;
    //选项位置的集合。初始的显示位置。用于后续拖动松手后，选项做回归动画
    private List<String> selectInitialLocationList;
    //分隔符
    private String SeparateSymbol = "-";
    //认为的最小滑动值。超过这个值，就认为是滑动；如果没有超过，就是认为是点击
    private int reputeMixMoveValue = 10;
    //按下时候的x,y坐标
    private float downX = 0;
    private float downY = 0;
    //当前点击或者按住了哪个选项
    private int currentOptionPosition = -1;
    //移动、滑动时候，当前位置的x,y坐标
    private float moveCurrentX;
    private float moveCurrentY;

    private String selectedContent = "";
    private final String correctAnswer = "选项2";
    private int wrongNum = 0;
    Timer timer = new Timer();


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_drag);

        tv_content = findViewById(R.id.tv_content);
        select_rl = findViewById(R.id.select_rl);
        rl_bg = findViewById(R.id.rl_bg);
        initData();
    }

    void initData(){
        selectInitialLocationList = new ArrayList<>();
        // 选项集合
        List<String> selectList = new ArrayList<>();
        selectList.add("选项1");
        selectList.add("选项2");
        selectList.add("选项3");
        this.selectList = selectList;

        answerSize = dp2px(50);
        halfAnswerSize = answerSize / 2;

        ViewTreeObserver.OnGlobalLayoutListener listener = new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {

                View view = new View(DragActivity.this);
                RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
                params.width = getScreenWidth()/2;
                params.height = getScreenHeight();
                view.setLayoutParams(params);
                view.setBackgroundColor(getResources().getColor(R.color.textGrayColor));
                rl_bg.addView(view);

                select_rl.getViewTreeObserver().removeOnGlobalLayoutListener(this);

                handleSelect();

            }
        };
        select_rl.getViewTreeObserver().addOnGlobalLayoutListener(listener);
    }


    @Override
    public boolean onTouchEvent(MotionEvent event) {
       switch (event.getAction()){
           case MotionEvent.ACTION_DOWN:
               if (moveTextView != null) {
                   break;
               }
               currentOptionPosition = -1;
               downX = event.getX();
               downY = event.getY();
               //指定当前滑动的TextView
               for (int i = 0; i < selectInitialLocationList.size(); i++) {

                   float x1 = Float.parseFloat(selectInitialLocationList.get(i).split(SeparateSymbol)[0]);
                   float x2 = x1 + answerSize*4;

                   float y1 = Float.parseFloat(selectInitialLocationList.get(i).split(SeparateSymbol)[1]);
                   float y2 = y1 + answerSize;

                   //x1、y1，是选项左上角的坐标。x2、y2，是选项右下角的坐标

                   if (downX > x1 && downX < x2 && downY > y1 && downY < y2) {
                       if(select_rl.getChildAt(i).getVisibility() == View.VISIBLE){
                           //拿到当前选择的这个选项的view
                           moveTextView = (TextView) select_rl.getChildAt(i);
                           //记下现在选的，是第几个选项
                           currentOptionPosition = i;
                           Log.e("按下", currentOptionPosition + "");
                           break;
                       }
                   }
               }
               break;
           case MotionEvent.ACTION_MOVE:
               if (moveTextView == null) {
                   return false;
               }
               moveCurrentX = event.getX();
               moveCurrentY = event.getY();

               if (Math.abs(moveCurrentX - downX) > reputeMixMoveValue && Math.abs(moveCurrentY - downY) > reputeMixMoveValue) {

                   //这里，按下的坐标，要减去选项的一半，让选项的中间，跟着手指动。否则，就是选项的左上角，跟着手指移动，不美观

                   moveTextView.setX(moveCurrentX - halfAnswerSize);
                   moveTextView.setY(moveCurrentY - halfAnswerSize);
               }
               break;
           case MotionEvent.ACTION_UP:
           case MotionEvent.ACTION_CANCEL:
               if (moveTextView == null) {
                   return false;
               }
               // 当移动到答案框内时
                if(moveCurrentX > tv_content.getX() && moveCurrentX < tv_content.getX() + tv_content.getWidth() &&
                    moveCurrentY >tv_content.getY() && moveCurrentY < tv_content.getY() + tv_content.getHeight()){
                    // 正确答案
                    if(selectList.get(currentOptionPosition).equals(correctAnswer)){
                        tv_content.setText(selectList.get(currentOptionPosition));
                        tv_content.setBackground(ResourcesCompat.getDrawable(getResources(),R.drawable.drag_success_bg, null));
                        moveTextView = null;
                        select_rl.getChildAt(currentOptionPosition).setVisibility(View.INVISIBLE);
                    }else{  // 错误答案
                        // 先抖一抖再回去
                        wrongAnimator();
                    }
                }else {
                    //说明没有放到答案框，就做回归动画
                    moveAnimator(0, 0, 0, 0, 0, -1);
                }
               break;
           default:
               break;
       }
       return true;
    }

    //处理选项。计算选项，摆放选项的位置
    private void handleSelect() {

        selectRootWidth = select_rl.getWidth();
        selectRootHeight = select_rl.getHeight();

        //移除之前的子控件（避免数据造成冲突）
        select_rl.removeAllViews();

        float x = 0;
        float y = 0;

        for (int i = 0; i < selectList.size(); i++) {

            String option = selectList.get(i);

            TextView tvAnswer = createSelectTv(option);

            x = getScreenWidth()*3/5;
            y = getScreenHeight()/4 + dp2px(80) * i;

            //这里的setX、setY，是指选项（正方形）左上角的坐标位置
            tvAnswer.setX(x);
            tvAnswer.setY(y);

            //保存这个选项的坐标位置
            selectInitialLocationList.add(x + SeparateSymbol + y);

            select_rl.addView(tvAnswer);
        }

    }

    /**
     * 创建选项TextView
     *
     * @param str textView上要展示的内容
     * @return
     */
    private TextView createSelectTv(String str) {

        TextView tv = new TextView(this);

        tv.setBackground(ResourcesCompat.getDrawable(getResources(),R.drawable.drag_default_bg,null));

        tv.setText(str);

        tv.setTextSize(TypedValue.COMPLEX_UNIT_DIP, 15);

        RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);

        params.width = answerSize*4;
        params.height = answerSize;
        tv.setLayoutParams(params);
        tv.setGravity(Gravity.CENTER);

        return tv;
    }

    // 抖一抖动画
    private void wrongAnimator(){
        wrongNum = wrongNum + 1;
        Animation anim = AnimationUtils.loadAnimation(DragActivity.this, R.anim.myanim);
        tv_content.setBackground(ResourcesCompat.getDrawable(getResources(), R.drawable.drag_error_bg, null));
        tv_content.setText(selectList.get(currentOptionPosition));
        tv_content.startAnimation(anim);
        moveTextView.setVisibility(View.GONE);
        //抖完后回去
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                runOnUiThread(() -> {
                    tv_content.setBackground(ResourcesCompat.getDrawable(getResources(), R.drawable.drag_default_bg, null));
                    tv_content.setText("");
                    moveAnimator(0, 0, 0, 0, 0, -1);
                });
            }
        }, 1200);
    }

    /**
     * 回归动画
     * type：
     * 0、没有拖动到空格处，松开手后控件回到初始位置
     * 1、拖动到空格处，松开手后，隐藏控件，静默回归
     * 2、点击选项，控件移动到空缺的位置
     * 3、点击选项，内容填充到空格处后，控件需要静默回归
     */
    private void moveAnimator(final int type, float sX, float sY, float eX, float eY, final int position) {

        Log.e("type is ", type + "");
        Log.e("currentOptionPosition ", currentOptionPosition + "");

        if (currentOptionPosition == -1 || moveTextView == null) {
            return;
        }
            moveTextView.setVisibility(View.VISIBLE);

        try {

            float startX = 0;
            float startY = 0;
            float endX = 0;
            float endY = 0;

            AnimatorSet animatorSet = new AnimatorSet();
            ObjectAnimator translationX;
            ObjectAnimator translationY;

            String location = selectInitialLocationList.get(currentOptionPosition);
            startX = moveTextView.getX();
            startY = moveTextView.getY();

            endX = Float.parseFloat(location.split(SeparateSymbol)[0]);
            endY = Float.parseFloat(location.split(SeparateSymbol)[1]);

            translationX = ObjectAnimator.ofFloat(
                    moveTextView,
                    "translationX",
                    startX,
                    endX
            );

            translationY = ObjectAnimator.ofFloat(
                    moveTextView,
                    "translationY",
                    startY,
                    endY
            );

            animatorSet.playTogether(translationX, translationY);

            long durationTime = 1000;

            animatorSet.setDuration(durationTime);

            animatorSet.addListener(new Animator.AnimatorListener() {
                @Override
                public void onAnimationStart(Animator animator) {


                }

                @Override
                public void onAnimationEnd(Animator animator) {

                        //抬起手后，释放滑动的TextView
                        moveTextView = null;
                        currentOptionPosition = -1;
                        if(wrongNum > 2){
                            for(int i = 0; i < select_rl.getChildCount(); i ++){
                                if(((TextView) select_rl.getChildAt(i)).getText().equals(correctAnswer)){
                                    ((TextView) select_rl.getChildAt(i)).setBackground(ResourcesCompat.getDrawable(getResources(),R.drawable.drag_hint_bg,null));
                                }
                            }
                        }

                }

                @Override
                public void onAnimationCancel(Animator animator) {

                }

                @Override
                public void onAnimationRepeat(Animator animator) {

                }
            });

            animatorSet.start();

        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    private int dp2px(float dpValue) {
        final float scale = getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }
}