我想从对话框更改图像按钮背景

Question

这是主要活动

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.dayyani.finalproject.MainActivity">

<ImageButton
    android:id="@+id/imageSelection"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="10sp"
    android:layout_width="80sp"
    android:layout_height="80sp"
    android:background="@drawable/profile"
    android:onClick="choseProfile"/>
<EditText
    android:id="@+id/firestEdit"
    android:layout_below="@+id/imageSelection"
    android:layout_centerHorizontal="true"
    android:layout_width="200sp"
    android:layout_height="wrap_content"
    android:layout_marginTop="20dp"/>
<EditText
    android:id="@+id/secondtEdit"
    android:layout_below="@+id/firestEdit"
    android:layout_centerHorizontal="true"
    android:layout_width="200sp"
    android:layout_height="wrap_content"/>

 package com.example.dayyani.finalproject;

import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageButton;


public class MainActivity extends AppCompatActivity {


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

    ImageButton imageSelection = (ImageButton) findViewById(R.id.imageSelection);
    EditText firstEdit = (EditText) findViewById(R.id.firestEdit);
    EditText secondtEdit = (EditText) findViewById(R.id.secondtEdit);
}


public void choseProfile(View v) {
    LayoutInflater inflater = this.getLayoutInflater();
    final View dialogView = inflater.inflate(R.layout.dialog_selection, null);
    final AlertDialog dialog = new AlertDialog.Builder(this)
            .setTitle("chose profile")
            .setView(dialogView)
            .setNegativeButton("back", null)
            .show();

}

public void changeImageBackground(View v) {
    View.OnClickListener change = new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            final ImageButton imageSelection = (ImageButton) findViewById(R.id.imageSelection);
            final ImageButton firstImage = (ImageButton) findViewById(R.id.firstImage);
            ImageButton secondImage = (ImageButton) findViewById(R.id.secondImage);
            ImageButton thirdImage = (ImageButton) findViewById(R.id.thirdImage);
            ImageButton fourthImage = (ImageButton) findViewById(R.id.fourthImage);


          firstImage.setOnClickListener(new View.OnClickListener() {
               @Override
               public void onClick(View view) {

                   imageSelection.setBackground(getDrawable(R.drawable.profile));
               }
           });

            secondImage.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    imageSelection.setBackground(getDrawable(R.drawable.profile2));
                }
            });

        }
    };
}

}

这是对话框

<?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">


<ImageButton
    android:id="@+id/firstImage"
    android:layout_width="80sp"
    android:layout_height="80sp"
    android:background="@drawable/profile"
    android:onClick="changeImageBackground"
    android:clickable="true"/>
<TextView
    android:id="@+id/firstText"
    android:layout_toRightOf="@+id/firstImage"
    android:layout_width="250sp"
    android:layout_height="80sp"
    android:text="firstImage"/>
<ImageButton
    android:id="@+id/secondImage"
    android:layout_below="@+id/firstImage"
    android:layout_width="80sp"
    android:layout_height="80sp"
    android:background="@drawable/profile2"
    android:onClick="changeImageBackground"
    android:clickable="true"/>
<TextView
    android:id="@+id/secondText"
    android:layout_toRightOf="@+id/secondImage"
    android:layout_below="@+id/firstText"
    android:layout_width="250sp"
    android:layout_height="80sp"
    android:text="secondImage"/>
<ImageButton
    android:id="@+id/thirdImage"
    android:layout_below="@+id/secondImage"
    android:layout_width="80sp"
    android:layout_height="80sp"
    android:clickable="true"/>
<TextView
    android:id="@+id/thirdText"
    android:layout_toRightOf="@+id/thirdImage"
    android:layout_below="@+id/secondText"
    android:layout_width="250sp"
    android:layout_height="80sp"
    android:text="thirdImage"/>
<ImageButton
    android:id="@+id/fourthImage"
    android:layout_below="@+id/thirdImage"
    android:layout_width="80sp"
    android:layout_height="80sp"
    android:clickable="true"/>
<TextView
    android:id="@+id/fourthText"
    android:layout_toRightOf="@+id/fourthImage"
    android:layout_below="@+id/thirdText"
    android:layout_width="250sp"
    android:layout_height="80sp"
    android:text="thirdImage"/>


</RelativeLayout>

我想要的是，如果我单击对话框上的图像，他将使用此图像背景并将其放在活动图像上

例如，当我在对话框中单击 firstImage 时，imageSelection 背景更改为 firstImage 背景

感谢您的帮助！！！！

Answer 1

通常，当您希望在 Fragment 和 Activity 之间进行通信时，您会使用接口。在这种情况下，我要做的是为您的 DialogFragment 设置一个单独的类，其中包括一个接口定义，当用户选择一个新的配置文件时，该接口将回调发送到 Main 活动。由于我在这方面还比较陌生，我发现自己完成设置很有帮助。这是我想出的。

DialogFragment 类向 MainActivity 发送回调，并通过可绘制资源 ID：

public class ChooseProfileDialog extends DialogFragment{

ImageButton imageSelection;
ImageButton firstImage;
ImageButton secondImage;


private OnProfileChangeListener mProfileChangeListener;

public ChooseProfileDialog() {
}

@NonNull
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {

    LayoutInflater inflater = getActivity().getLayoutInflater();
    final View dialogView = inflater.inflate(R.layout.dialog_selection, null);
    final AlertDialog.Builder dialog = new AlertDialog.Builder(getActivity())
            .setTitle("chose profile")
            .setView(dialogView)
            .setNegativeButton("back", null);

    imageSelection = (ImageButton) dialogView.findViewById(R.id.imageSelection);
    firstImage = (ImageButton) dialogView.findViewById(R.id.firstImage);
    secondImage = (ImageButton) dialogView.findViewById(R.id.secondImage);


    // Callbacks to MainActivity
    firstImage.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            // Call onProfileSelection in the MainActivity and pass the resource ID
            mProfileChangeListener.onProfileSelection(R.drawable.profile);
            dismiss();
        }
    });

    secondImage.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            // Call onProfileSelection in the MainActivity and pass the resource ID
            mProfileChangeListener.onProfileSelection(R.drawable.profile2);
            dismiss();
        }
    });


    return dialog.create();
}


public interface OnProfileChangeListener {
    // method called
    public void onProfileSelection(int backgroundResourceId);
}


// When the dialog attaches to MainActivity, check that the interface has been implemented

@Override
public void onAttach(Context context) {
    super.onAttach(context);

    // Check that the MainActivity implements your interface
    try {
        mProfileChangeListener = (OnProfileChangeListener) getActivity();
    } catch (ClassCastException e){
        throw new ClassCastException(getContext().toString() + "must implement the OnProfilechangeListener interface.");
    }


}

}

MainActivity 实现接口并覆盖 onProfileSelection 方法：

public class MainActivity extends AppCompatActivity implements ChooseProfileDialog.OnProfileChangeListener {

ImageButton imageSelection;
EditText firstEdit;
EditText secondtEdit;


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

    imageSelection = (ImageButton) findViewById(R.id.imageSelection);
    firstEdit = (EditText) findViewById(R.id.firestEdit);
    secondtEdit = (EditText) findViewById(R.id.secondtEdit);
}


public void choseProfile(View v) {
    ChooseProfileDialog dialog = new ChooseProfileDialog();
    dialog.show(getSupportFragmentManager(),"CHOOSE_PROFILE_TAG");
}

// Define what happens when the callback from ChooseProfileDialog in invoked
@Override
public void onProfileSelection(int backgroundResourceId) {
    imageSelection.setImageResource(backgroundResourceId);
}
}

这也可能有用：https://developer.android.com/training/basics/fragments/communicating.html

Answer 2

我在移动设备上尝试此操作，但出现错误 java.lang.NullPointerException: Attempt to invoke interface method 'void com.example.dayyani.finalproject.ChooseProfileDialog$OnProfileChangeListener.onProfileSelection(int)' on an null object reference