Intent启动Activity,启动子Activity,从子Activity返回值

最新推荐文章于 2024-04-13 19:17:10 发布

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最新推荐文章于 2024-04-13 19:17:10 发布

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本文链接：https://blog.youkuaiyun.com/qq_39014426/article/details/80932745

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本文展示了如何在Android应用中使用Intent启动子Activity，并从子Activity返回数据到父Activity。通过创建MainActivity和Sub_Activity，点击按钮启动子Activity，用户输入数据后，点击返回按钮将数据封装在Intent中传回给父Activity。

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MainActivity.java

package com.example.administrator.exp4;

import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

private static final int REQUEST_CODE=1;
TextView textView;

@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 view) {
Intent intent=new Intent(MainActivity.this,Sub_Activity.class);
startActivityForResult(intent,REQUEST_CODE);
}
});
}

@Override
protected void onActivityResult(int requestCode,int resultCode,Intent data){
super.onActivityResult(requestCode,resultCode,data);
switch (requestCode){
case REQUEST_CODE:
if(resultCode==RESULT_OK){
Uri uriData=data.getData();
textView=(TextView)findViewById(R.id.textView);
textView.setText(uriData.toString());
}
else if(resultCode==RESULT_CANCELED){
break;
}
}
}

}

Sub_Activity.java

package com.example.administrator.exp4;

import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class Sub_Activity extends AppCompatActivity {

private EditText editText;

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

editText=(EditText)findViewById(R.id.editView);

Button button=(Button)findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String uriString=editText.getText().toString();
Uri data=Uri.parse("用户名："+uriString);
Intent result=new Intent(null,data);
setResult(RESULT_OK,result);
finish();
}
});
}

}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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:layout_gravity="center">

<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="登陆"
android:layout_marginLeft="8dp"
app:layout_constraintLeft_toLeftOf="parent"
android:layout_marginRight="8dp"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="8dp"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_marginBottom="8dp"
app:layout_constraintVertical_bias="0.366" />

<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="用户名："
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="8dp"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_marginBottom="8dp"
android:layout_marginRight="8dp"
app:layout_constraintRight_toRightOf="parent"
android:layout_marginLeft="8dp"
app:layout_constraintLeft_toLeftOf="parent" />

</android.support.constraint.ConstraintLayout>

activity_sub_.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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"
>

<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="返回"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="8dp"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_marginBottom="8dp"
android:layout_marginLeft="8dp"
app:layout_constraintLeft_toLeftOf="parent"
android:layout_marginRight="8dp"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintVertical_bias="0.53"
app:layout_constraintHorizontal_bias="0.46" />

<LinearLayout
android:id="@+id/linearLayout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginTop="8dp"
android:gravity="center"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0.481"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.373">

<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="用户名："
tools:layout_editor_absoluteX="163dp"
tools:layout_editor_absoluteY="233dp" />

<EditText
android:id="@+id/editView"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>

</android.support.constraint.ConstraintLayout>