startActivityForResult(intent,requestCode)可以调用另外一个Activity,并返回结果。
换头像案例
activity_main.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=".MainActivity">
<ImageView
android:id="@+id/imageView"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_gravity="center"
android:src="@drawable/tx"/>
<Button
android:id="@+id/btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="选择头像"
android:textSize="26sp"/>
</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
tools:context=".HeadActivity">
<GridView
android:id="@+id/gridView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="10dp"
android:horizontalSpacing="3dp"
android:verticalSpacing="3dp"
android:numColumns="4"/>
</RelativeLayout>
MainActivity.java
package com.example.startactivityforresult;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.os.PersistableBundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btn = (Button) findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this,
HeadActivity.class);
startActivityForResult(intent,0x11);
}
});
}
/**该方法用于获取返回结果**/
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
//判断请求码和返回码是不是一致
if (requestCode == resultCode){
Bundle bundle = data.getExtras();
int imageId = bundle.getInt("imageId");
ImageView imageView = (ImageView) findViewById(R.id.imageView);
imageView.setImageResource(imageId);
}
}
}
HeadActivity.java
package com.example.startactivityforresult;
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 {
public int[] imageId = new int[]{
R.drawable.tx1,R.drawable.tx2,R.drawable.tx3,R.drawable.tx4
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_head);
GridView gridView = (GridView) findViewById(R.id.gridView);
BaseAdapter adapter = new BaseAdapter() {
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageview;
if(convertView == null){
imageview = new ImageView(HeadActivity.this);
imageview.setAdjustViewBounds(true);
imageview.setMaxHeight(150);
imageview.setPadding(5,5,5,5);
}else{
imageview = (ImageView)convertView;
}
imageview.setImageResource(imageId[position]);
return imageview;
}
@Override
public Object getItem(int position) {
return position;
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public int getCount() {
return imageId.length;
}
};
gridView.setAdapter(adapter);
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(0x11,intent);
finish();
}
});
}
}
效果: