安卓7~8

2023-11-03 20:06:10

1.三个界面，界面1点击按钮使用显式意图开启界面2.界面2点击按钮隐式意图开启界面3

<?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">

    <Button
        android:id="@+id/bt_1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#F2B4FC"
        android:text="显示意图开启界面2"
        android:textSize="20sp"
        android:textColor="#000000"
        android:layout_marginTop="20dp"
        android:layout_marginLeft="10dp"/>

</LinearLayout>

package com.example.homework11;

import androidx.appcompat.app.AppCompatActivity;

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

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button btn1=(Button)findViewById(R.id.bt_1);
        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent(MainActivity.this,Main2Activity.class);
                startActivity(intent);
            }
        });
    }
}

<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=".Main2Activity">

    <Button
        android:id="@+id/bt_2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#EEA6BF"
        android:text="隐式意图开启界面3"
        android:textSize="20sp"
        android:textColor="#000000"
        android:layout_marginLeft="10dp"
        android:layout_marginTop="20dp"/>

</LinearLayout>

package com.example.homework11;

import androidx.appcompat.app.AppCompatActivity;

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

public class Main2Activity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        Button btn2=(Button)findViewById(R.id.bt_2);
        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent();
                intent.setAction("com.ym.second");
                startActivity(intent);
            }
        });
    }
}

<?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"
    android:background="#A5D4FA"
    tools:context=".Main3Activity">

    <TextView
        android:id="@+id/tv_1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="界面3"
        android:textSize="20sp"
        android:layout_centerInParent="true"
        android:textColor="#000000"/>

</RelativeLayout>

<activity android:name=".Main3Activity">
            <intent-filter>
                <action android:name="com.ym.second" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity android:name=".Main2Activity" >
        </activity>
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

2.在界面1做一个按钮开启浏览器访问百度

<?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"
    android:background="#F7DDFC"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/bt_1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#77DDEB"
        android:text="显式意图开启界面2"
        android:textSize="20sp"
        android:layout_marginTop="20dp"
        android:layout_marginLeft="20dp"/>
    <Button
        android:id="@+id/bt_3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#56AEF5"
        android:text="开启浏览器访问百度"
        android:textSize="20sp"
        android:layout_marginTop="20dp"
        android:layout_marginLeft="20dp"
        android:padding="10dp"
        android:onClick="click3"/>

</LinearLayout>

package com.example.homework12;

import androidx.appcompat.app.AppCompatActivity;

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

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button btn1=(Button)findViewById(R.id.bt_1);
        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent(MainActivity.this,Main2Activity.class);
                startActivity(intent);
            }
        });
    }
    public void click3(View view){
        Intent intent=new Intent();
        intent.setAction("android.intent.action.VIEW");
        intent.setData(Uri.parse("http://www.baidu.com"));
        startActivity(intent);
    }
}

3.2个edittext,4个按钮一个textview，实现简单计算器。

<?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"
    android:id="@+id/a_1"
    android:background="#F1B3FC"
    tools:context=".MainActivity">
    <TextView
        android:id="@+id/tv_1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="计算器"
        android:textSize="25dp"
        android:layout_margin="20dp" />

    <EditText
        android:id="@+id/et_1"
        android:layout_width="200dp"
        android:layout_height="wrap_content"
        android:hint="请输入一个数"
        android:layout_marginLeft="100dp"
        android:layout_marginRight="100dp"
        android:layout_marginTop="100dp"
        android:inputType="number"
        android:gravity="center"
        android:textSize="20sp"/>
    <EditText
        android:id="@+id/et_2"
        android:layout_width="200dp"
        android:layout_height="wrap_content"
        android:hint="请输入一个数"
        android:layout_marginLeft="100dp"
        android:layout_marginRight="100dp"
        android:inputType="number"
        android:gravity="center"
        android:textSize="20sp" />
    <LinearLayout
        android:id="@+id/a_2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:layout_marginTop="20dp"
        android:layout_marginRight="20dp"
        android:layout_marginLeft="20dp">
        <Button
            android:id="@+id/bt_1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="加(+)"
            android:background="#F7BACE"/>
        <Button
            android:id="@+id/bt_2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="减(-)"
            android:background="#F7BACE" />
        <Button
            android:id="@+id/bt_3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="乘(*)"
            android:background="#F7BACE"/>
        <Button
            android:id="@+id/bt_4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="除(/)"
            android:background="#F7BACE"/>
    </LinearLayout>
    <TextView
        android:id="@+id/tv_2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="结果="
        android:textSize="25sp"
        android:textColor="#000000"
        android:layout_marginLeft="150dp"
        android:layout_marginRight="150dp"
        android:layout_marginTop="50dp"
        android:gravity="center"/>


</LinearLayout>

package com.example.homework13;

import androidx.appcompat.app.AppCompatActivity;

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

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        findViewById(R.id.bt_1).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String num1=((EditText)(findViewById(R.id.et_1))).getText().toString();//获取et_1上面的文本，并转成字符串
                String num2=((EditText)(findViewById(R.id.et_2))).getText().toString();//获取et_2上面的文本，并转成字符串

                int n1= Integer.parseInt(num1);
                int n2= Integer.parseInt(num2);
                int sum=n1+n2;
                TextView tv_1=findViewById(R.id.tv_2);//获取TextView 控件
                tv_1.setText("结果="+sum);
            }
        });
        findViewById(R.id.bt_2).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String num1=((EditText)(findViewById(R.id.et_1))).getText().toString();
                String num2=((EditText)(findViewById(R.id.et_2))).getText().toString();
                int n1=Integer.parseInt(num1);
                int n2=Integer.parseInt(num2);
                int sum=n1-n2;
                TextView tv_1=findViewById(R.id.tv_2);
                tv_1.setText("结果="+sum);
            }
        });
        findViewById(R.id.bt_3).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String num1=((EditText)(findViewById(R.id.et_1))).getText().toString();
                String num2=((EditText)(findViewById(R.id.et_2))).getText().toString();
                int n1=Integer.parseInt(num1);
                int n2=Integer.parseInt(num2);
                int sum=n1*n2;
                TextView tv_1=findViewById(R.id.tv_2);
                tv_1.setText("结果="+sum);
            }
        });
        findViewById(R.id.bt_4).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String num1=((EditText)(findViewById(R.id.et_1))).getText().toString();
                String num2=((EditText)(findViewById(R.id.et_2))).getText().toString();
                int n1=Integer.parseInt(num1);
                int n2=Integer.parseInt(num2);
                int sum=n1/n2;
                TextView tv_1=findViewById(R.id.tv_2);
                tv_1.setText("结果="+sum);
            }
        });
    }
}

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