使用 Intent 的 Activity 中的 Android Activity

Question

我有一个 Activity 有 2 个按钮，点击它会进入第二个和第三个 Activity 。第二个 Activity 有 2 个按钮“返回主 Activity ”和“点击第三个 Activity ”。当我点击“返回主 Activity 按钮”时，它不会返回到主 Activity 屏幕但是当我点击“转到第三个 Activity ”按钮时，它会转到第三个 Activity 。 谁能帮我解释为什么我的“返回主 Activity 按钮”不起作用？

这是我的代码

main activity
{
package com.example.aditya.activitywithinactivity;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.view.View.OnClickListener;

import static com.example.aditya.activitywithinactivity.R.id.start;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

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

        Button bttn1 = (Button) findViewById(R.id.button1);
        bttn1.setOnClickListener(MainActivity.this);
        Button bttn2 = (Button) findViewById(R.id.button2);
        bttn2.setOnClickListener(MainActivity.this);
    }
    public void onClick(View v) {
        switch (v.getId()) {

            case R.id.button1: {
                Intent intent = new Intent(MainActivity.this, SecondActivity.class);
                startActivity(intent);
            }
            case R.id.button2: {
                Intent intent1 = new Intent(MainActivity.this, ThirdActivity.class);
                startActivity(intent1);
            }
        }
    }
    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);
        setContentView(R.layout.activity_main);

    };
}

第二个 Activity .java

package com.example.aditya.activitywithinactivity;

import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.Button;

public class SecondActivity extends AppCompatActivity implements View.OnClickListener {

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

        Button bttn3 = (Button) findViewById(R.id.button3);
        bttn3.setOnClickListener(SecondActivity.this);
        Button bttn4 = (Button) findViewById(R.id.button4);
        bttn4.setOnClickListener(SecondActivity.this);
    }
    public void onClick(View v) {
        switch (v.getId()) {

            case R.id.button3: {
                Intent intent2 = new Intent(this, MainActivity.class);
                intent2.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
                intent2.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
                startActivity(intent2);
            }
            case R.id.button4: {
                Intent intent3 = new Intent(SecondActivity.this, ThirdActivity.class);
                startActivity(intent3);
            }
        }
    };
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical">

    <EditText
        android:id="@+id/myText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="buttonClicked"
        android:text="Click to go to Secondary Activity" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="buttonClicked"
        android:text="Click to go to Third Activity" />

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

</LinearLayout>

activity_second

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/myText2" />
    <Button
        android:id="@+id/button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="buttonClicked"
        android:text="Return to Main Activity"/>
    <Button
        android:id="@+id/button4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="buttonClicked"
        android:text="Click to go to Third Activity"/>

</LinearLayout>

Answer 1

试试这个:

public void onClick(View v) {
    switch (v.getId()) {

        case R.id.button3: {
            Intent intent2 = new Intent(SecondActivity.this, MainActivity.class);

            startActivity(intent2);
            break;
        }
        case R.id.button4: {
            Intent intent3 = new Intent(SecondActivity.this, ThirdActivity.class);
            startActivity(intent3);
           break;
        }
    }
};