03-Android基础知识-04-Android 中 Activity 启动模式

标准启动模式：

 

 MainActivity.java:

package com.imooc.launchmode;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private TextView tv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView) findViewById(R.id.tv);

        tv.setText(String.format("TaskID:%d
,Curren Activity id%s",getTaskId(),toString()));

        findViewById(R.id.btnStarSelf).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v){
            }
        });
    }
}

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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"
        tools:context=".MainActivity">

        <TextView
            android:id="@+id/tv"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hello World!"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/btnStarSelf"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="启动MainActivity"
        tools:layout_editor_absoluteX="100dp"
        tools:layout_editor_absoluteY="157dp" />


</androidx.constraintlayout.widget.ConstraintLayout>

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 　　activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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"
        tools:context=".MainActivity">
        <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical">

                <TextView
                    android:id="@+id/tv"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="Hello World!"
                    app:layout_constraintBottom_toBottomOf="parent"
                    app:layout_constraintLeft_toLeftOf="parent"
                    app:layout_constraintRight_toRightOf="parent"
                    app:layout_constraintTop_toTopOf="parent" />

                <Button
                android:id="@+id/btnMainAty"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="启动MainActivity"

                    tools:ignore="MissingConstraints" />

                <Button
                android:id="@+id/btnStarBAty"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="启动BAty"

                    tools:ignore="MissingConstraints" />
        </LinearLayout>


</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java:

package com.imooc.launchmode;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private TextView tv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView) findViewById(R.id.tv);

        tv.setText(String.format("TaskID:%d
,Curren Activity id%s",getTaskId(),toString()));

        findViewById(R.id.btnMainAty).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v){
                startActivity(new Intent(MainActivity.this,MainActivity.class));
            }
        });

        findViewById(R.id.btnStarBAty).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(MainActivity.this,BAty.class));
            }
        });
    }
}

BAty.java:

package com.imooc.launchmode;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class BAty extends AppCompatActivity {

    private TextView tv;

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

        tv = (TextView) findViewById(R.id.tv);

        tv.setText(String.format("TaskID:%d
,Curren Activity id%s",getTaskId(),toString()));

        findViewById(R.id.btnMainAty).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v){
                startActivity(new Intent(BAty.this,MainActivity.class));
            }
        });

        findViewById(R.id.btnStarBAty).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                startActivity(new Intent(BAty.this,BAty.class));
            }
        });
    }
}

activity-baty.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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"
    tools:context=".BAty">

    <TextView android:id = "@+id/tv" android:text="Hello world!" android:layout_width="wrap_content" android:layout_height="wrap_content"
        />

    <Button
        android:id="@+id/btnMainAty"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="启动MainActivity"

        tools:ignore="MissingConstraints" />

    <Button
        android:id="@+id/btnStarBAty"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="启动BAty" />

</androidx.constraintlayout.widget.ConstraintLayout>