scene

Click the button in Android to start another Activity and transfer values between activities:

https://blog.csdn.net/BADAO_LIUMANG_QIZHI/article/details/103919470

How to get the return value of Acitvity after launching Activity and Value Transfer above.The following example implements clicking the Select Avatar button, jumping to the avatar display activity, and returning the index of the selected picture to set the avatar after getting it in MainActivity.

Effect

 

 

Note:

Blog:
https://blog.csdn.net/badao_liumang_qizhi
Focus on Public Number
Domineering program ape
Get programming-related e-books, tutorial pushes, and free downloads.

Realization

First, the layout of the main page, MainActivity, adds a Select Avatar button and an ImageView to display the avatar.

<?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=".MainActivity">

<ImageView
    android:id="@+id/image"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"/>

<Button
    android:id="@+id/button"
    android:text="Select Avatar"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"/>

</LinearLayout>

Then in the OnCreate method in MainActivity, using startActivityForResult, you can start another Activity and get the results back.

To set a request code, here is 200.

        Button button = (Button)findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this,HeadActivity.class);
                startActivityForResult(intent,200);
            }
        });

Then jump to the second Activity to select the avatar.First set its layout file and add a GridView to display the avatar photo you want to select.

activity_head.xml

<?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=".HeadActivity">

    <GridView
        android:id="@+id/gridView"
        android:numColumns="4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

</LinearLayout>

Then come to its Activity and use the adapter to set its photo source.

First declare an array of pictures

    private  int[] imageId = new int[]{
        R.drawable.img1,R.drawable.img2
    };

Here's a reference to two portrait photos under drawable.

Then use the adapter to set the data source for the photo

        GridView gridView = (GridView) findViewById(R.id.gridView);
        BaseAdapter adapter = new BaseAdapter() {
            @Override
            public int getCount() {
                return imageId.length;
            }

            @Override
            public Object getItem(int position) {
                return null;
            }

            @Override
            public long getItemId(int position) {
                return 0;
            }

            @Override
            public View getView(int position, View convertView, ViewGroup parent) {
                ImageView imageView;
                if(convertView ==null)
                {
                    imageView = new ImageView(HeadActivity.this);
                    imageView.setAdjustViewBounds(true);
                    imageView.setMaxWidth(158);
                    imageView.setMaxHeight(150);
                    imageView.setPadding(5, 5, 5, 5);

                }else
                {
                    imageView = (ImageView) convertView;
                }
                imageView.setImageResource(imageId[position]);
                return imageView;
            }
        };

        gridView.setAdapter(adapter);

Then click on the event listener for the gridView option to get an index of the selected photo and return the data through the putInt of the Bundle object and the putExtras of the intent object.Then call setResult(200,intent); return the result, where the request result code is also set to 200.

Full HeadActivity.java

package com.badao.selectimage;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;

public class HeadActivity extends AppCompatActivity {

    private  int[] imageId = new int[]{
        R.drawable.img1,R.drawable.img2
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {        GridView gridView = (GridView) findViewById(R.id.gridView);
        BaseAdapter adapter = new BaseAdapter() {
            @Override
            public int getCount() {
                return imageId.length;
            }

            @Override
            public Object getItem(int position) {
                return null;
            }

            @Override
            public long getItemId(int position) {
                return 0;
            }

            @Override
            public View getView(int position, View convertView, ViewGroup parent) {
                ImageView imageView;
                if(convertView ==null)
                {
                    imageView = new ImageView(HeadActivity.this);
                    imageView.setAdjustViewBounds(true);
                    imageView.setMaxWidth(158);
                    imageView.setMaxHeight(150);
                    imageView.setPadding(5, 5, 5, 5);

                }else
                {
                    imageView = (ImageView) convertView;
                }
                imageView.setImageResource(imageId[position]);
                return imageView;
            }
        };

        gridView.setAdapter(adapter);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_head);

        gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Intent intent = getIntent();
                Bundle bundle = new Bundle();
                bundle.putInt("imageId",imageId[position]);
                intent.putExtras(bundle);
                setResult(200,intent);
                finish();
            }
        });
    }
}

Then go back to how MainActivity accepts the returned results.

ctrl + O override method onActivityResult, if request code and return result code are both 200, pass first

Bundle bundle  = data.getExtras();

Gets the Bundle object.

Then pass

int imageId = bundle.getInt("imageId");

Gets the returned photo index data.

Then set the photo source for ImageView.

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(requestCode ==200 && resultCode == 200)
        {
            Bundle bundle  = data.getExtras();
            int imageId = bundle.getInt("imageId");
            ImageView imageView = (ImageView) findViewById(R.id.image);
            imageView.setImageResource(imageId);

        }
    }

MainActivity full sample code

package com.badao.selectimage;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(requestCode ==200 && resultCode == 200)
        {
            Bundle bundle  = data.getExtras();
            int imageId = bundle.getInt("imageId");
            ImageView imageView = (ImageView) findViewById(R.id.image);
            imageView.setImageResource(imageId);

        }
    }

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

        Button button = (Button)findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this,HeadActivity.class);
                startActivityForResult(intent,200);
            }
        });


    }
}