有条件的拖放图像

Conditional Drag & Drop of images

因为我是新手,所以我会问一个问题,这个问题对你们中的许多人来说可能非常简单,但是我,我整天都在学习教程以了解它是如何工作的,但不幸的是我不是那个幸运.

我正在构建一个儿童应用程序,他们必须将动物图像拖到相应的阴影上。因此在下面的示例中,他们必须将奶牛的图像拖到奶牛的阴影上。

如果他们将它拖到错误的图像上,将会有声音通知这样说,如果他们将它拖到正确的图像上,图像将替换阴影,并且会有确认声音。

到目前为止,我设法编写了将奶牛图像拖到任何阴影上并替换它们的部分。我想只在正确的时候更换。

我将在我的代码下方添加,希望有人能够帮助我!

这是xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/animals_types"
    android:textSize="25sp"
    android:id="@+id/gamesCategory"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:text="@string/games_cow"
    android:paddingTop="20dp"
    android:paddingBottom="20dp"
    android:textSize="35sp"
    android:id="@+id/text_cow"
    android:layout_below="@+id/gamesCategory"
    android:layout_centerHorizontal="true" />

<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/games_cow"
    android:layout_below="@+id/text_cow"
    android:layout_centerHorizontal="true"
    android:maxHeight="150dp"
    android:maxWidth="150dp"
    android:scaleType="fitCenter"
    android:adjustViewBounds="true"
    android:id="@+id/games_cow_item" />

<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/games_cow_shadow"
    android:maxHeight="150dp"
    android:maxWidth="150dp"
    android:scaleType="fitCenter"
    android:adjustViewBounds="true"
    android:layout_centerHorizontal="true"
   android:layout_marginLeft="20dp"
    android:layout_marginStart="20dp"
    android:layout_below="@+id/games_cow_item"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:id="@+id/games_cow_shadow"/>

<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/games_pig_shadow"
    android:maxHeight="130dp"
    android:maxWidth="130dp"
    android:scaleType="fitCenter"
    android:adjustViewBounds="true"
    android:layout_centerHorizontal="true"
    android:layout_marginRight="20dp"
    android:layout_marginEnd="20dp"
    android:layout_below="@+id/games_cow_item"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:id="@+id/games_pig_shadow"/>

<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/games_horse_shadow"
    android:maxHeight="150dp"
    android:maxWidth="150dp"
    android:scaleType="fitCenter"
    android:adjustViewBounds="true"
    android:layout_centerHorizontal="true"
    android:layout_margin="20dp"
    android:layout_below="@+id/games_cow_shadow"
    android:id="@+id/games_horse_shadow"/>

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="NEXT"
    android:id="@+id/button5"
    android:layout_below="@+id/games_horse_shadow"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="BACK"
    android:id="@+id/button6"
    android:layout_alignTop="@+id/button5"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

</RelativeLayout>

这是Java:

 package com.gadgetcatch.firstwords;

import android.content.ClipData;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.view.DragEvent;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;

/**
 * Created by Alex on 2/1/2016.
 */
public class GamesAnimals extends AppCompatActivity {

    private ImageView option, choice1, choice2, choice3;

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.games_animals);

        android.support.v7.app.ActionBar actionBar = getSupportActionBar();
        assert actionBar != null;
        actionBar.setDisplayShowHomeEnabled(true);
        actionBar.setIcon(R.mipmap.ic_launcher);

        //View to drag

        option = (ImageView)findViewById(R.id.games_cow_item);

        //Views to drop unto

        choice1 = (ImageView)findViewById(R.id.games_cow_shadow);
        choice2 = (ImageView)findViewById(R.id.games_pig_shadow);
        choice3 = (ImageView)findViewById(R.id.games_horse_shadow);

        //set touch listener

        option.setOnTouchListener(new ChoiceTouchListener());

        //set drag listeners

        choice1.setOnDragListener(new ChoiceDragListener());
        choice2.setOnDragListener(new ChoiceDragListener());
        choice3.setOnDragListener(new ChoiceDragListener());


    }

    private final class ChoiceTouchListener implements View.OnTouchListener{
        public boolean onTouch(View view, MotionEvent motionEvent){
            if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {

                //setup drag
                ClipData data = ClipData.newPlainText("", "");
                View.DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);

                //start dragging the item touched
                view.startDrag(data, shadowBuilder, view, 0);

                return true;
            }
            else {
                return false;
            }
        }
    }


    private class ChoiceDragListener implements View.OnDragListener{
        @Override
        public boolean onDrag(View v, DragEvent event) {
            //handle drag events
            switch (event.getAction()) {
                case DragEvent.ACTION_DRAG_STARTED:
                    //no action necessary
                    break;
                case DragEvent.ACTION_DRAG_ENTERED:
                    //no action necessary
                    break;
                case DragEvent.ACTION_DRAG_EXITED:
                    //no action necessary
                    break;
                case DragEvent.ACTION_DROP:
                    //handle the dragged view being dropped over a drop view - asta de deasupra
                    //handle the dragged view being dropped over a target view -asta de jos
                    View view = (View) event.getLocalState();
                    //stop displaying the view where it was before it was dragged
                    view.setVisibility(View.INVISIBLE);
                    //view dragged item is being dropped on
                    ImageView dropTarget = (ImageView) v;
                    //view being dragged and dropped
                    ImageView dropped = (ImageView) view;
                    //update the image in the target view to reflect the data being dropped
                    dropTarget.setImageDrawable(dropped.getDrawable());

                    break;
                case DragEvent.ACTION_DRAG_ENDED:
                    //no action necessary
                    break;
                default:
                    break;
            }

            return true;
        }
    }
}

这是 .xml 的图片,以防我解释得不够好。

提前感谢您的任何建议! cow_image

你快完成了:)你只需要检查图像是否正确。从您的代码中,我看到缺少所有逻辑。有上百万种方法可以做到这一点,但我建议您使用视图的 TAG 属性 来存储有关每个图像的信息。

A Tag 是您可以存储在任何视图上的东西。它可以是一个 String,一个数字,等等。为了清楚起见,我们使用 String我们将设置相同的 TAG 以匹配图像/阴影:

  • Image COW SHADOW 将具有标签 "COW",与 Image COW
  • 相同
  • 图片 PIG SHADOW 将具有标签 "PIG",与图片 PIG 相同。
  • Image HORSE SHADOW 将具有标签 "HORSE",与 Image Horse 相同。

然后在你的情况下ACTION_DROP,你将检查阴影和拖放图像的标签是否相同,如下所示:

   .
   .
   .
   case DragEvent.ACTION_DROP:
       .
       .
       .
       // view dragged item is being dropped on
       ImageView dropTarget = (ImageView) v;
       // view being dragged and dropped
       ImageView dropped = (ImageView) view;

       String tagDropTarget = (String)dropTarget.getTag(),
              tagDroppedImage = (String)dropped.getTag();

       if ((tagDropTarget != null) && (tagDropTarget.equals (tagDroppedImage)) {

            // yippie! correct!!
            // update the image in the target view to reflect the data being dropped

            dropTarget.setImageDrawable(dropped.getDrawable());
        } else {
            // oppps, wrong!!!!
            .
            .
        }
        break;

现在我们需要在 XML:

中设置标签
<ImageView
    android:tag="COW"
    .
    .
    android:src="@drawable/games_cow"
    android:id="@+id/games_cow_item" />

<ImageView
    android:tag="COW"
    .
    .
    android:src="@drawable/games_cow_shadow"
    android:id="@+id/games_cow_shadow"/>

<ImageView
    android:tag="PIG"
    .
    .
    android:src="@drawable/games_pig_shadow"
    android:id="@+id/games_pig_shadow"/>

<ImageView
    android:tag="HORSE"
    .
    .
    android:src="@drawable/games_horse_shadow"
    android:id="@+id/games_horse_shadow"/>