Android第四次作业

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
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"
    tools:context=".Demo11Activity"
    android:orientation="vertical">

    <Button
        android:id="@+id/anniu1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="anniu1"
        android:layout_gravity="center"
        />
    <Button
        android:id="@+id/anniu11"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="百度"
        android:layout_gravity="center"/>


</LinearLayout>

<?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"
    tools:context=".Demo22Activity"
    android:orientation="vertical">

    <Button
        android:id="@+id/anniu2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="anniu2"
        android:layout_gravity="center"/>

</LinearLayout>

<?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"
    tools:context=".Demo33Activity"
    android:orientation="vertical">

    <Button
        android:id="@+id/anniu3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="anniu3"
        android:layout_gravity="center"
        />

</LinearLayout>

package com.example.myapplication;

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 Demo11Activity extends AppCompatActivity {

    private Button btn1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_demo11);

        btn1=findViewById(R.id.anniu1);
        Button btn2=findViewById(R.id.anniu11);
        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent(Demo11Activity.this,Demo22Activity.class);
                startActivityForResult(intent,1);
                finish();
            }
        });
        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent();
                intent.setAction("android.intent.action.VIEW");
                intent.setData(Uri.parse("http://www.baidu.com"));
                startActivity(intent);
            }
        });
    }
}

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;

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

public class Demo22Activity extends AppCompatActivity {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_demo22);

        Button btn2=findViewById(R.id.anniu2);
        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent();
                intent.setAction("cn.itcast.START_ACTIVITY");
                intent.addCategory("android.intent.category.DEFAULT");
                startActivity(intent);

            }
        });
    }
}

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

public class Demo33Activity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_demo33);
    }
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.myapplication">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".Demo7Activity">

        </activity>
        <activity android:name=".Demo33Activity">
            <intent-filter>
                <action android:name="cn.itcast.START_ACTIVITY" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity android:name=".Demo22Activity"></activity>
        <activity android:name=".Demo11Activity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

        </activity>
        <activity android:name=".Demo6Activity"></activity>
        <activity android:name=".Demo5Activity" />
        <activity android:name=".Demo4Activity" />
        <activity android:name=".Main2Activity" />
        <activity android:name=".Demo3Activity" />
        <activity android:name=".Demo2Activity" />
        <activity android:name=".Demo1Activity" />
        <activity android:name=".MainActivity" />
    </application>

</manifest>

 

 

3.2个edittext,4个按钮一个textview，实现简单计算器。

提示1：如何获取edittext上的数据？
String num1=((EditText)(findViewById(R.id.et1))).getText().toString();//获取et1上面的文本，并 
转成字符串
提示2：字符串如何转int
int n1=Integer.parseInt(num1);
提示3:如何把计算结果显示在textview上？
TextView tv1=(TextView)findViewById(R.id.tv1);//获取控件
tv1.setText("1233213");//用settext方法赋值

<?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"
    tools:context=".Demo7Activity"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <TextView
            android:id="@+id/tv1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="数字1"
            android:textSize="50dp"/>
        <EditText
            android:id="@+id/et1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="请输入数字"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <TextView
            android:id="@+id/tv2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="数字2"
            android:textSize="50dp"/>
        <EditText
            android:id="@+id/et2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="请输入数字"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <Button
            android:id="@+id/btn1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="+"
            android:layout_weight="1"/>
        <Button
            android:id="@+id/btn2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="-"
            android:layout_weight="1"/>
        <Button
            android:id="@+id/btn3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="*"
            android:layout_weight="1"/>
        <Button
            android:id="@+id/btn4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="/"
            android:layout_weight="1"/>
    </LinearLayout>
    <TextView
        android:id="@+id/tv3"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="结果为："
        android:textSize="50dp"/>

</LinearLayout>

package com.example.myapplication;

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;

import org.w3c.dom.Text;

public class Demo7Activity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_demo7);

        //+
        findViewById(R.id.btn1).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String num1=((EditText)(findViewById(R.id.et1))).getText().toString();
                String num2=((EditText)(findViewById(R.id.et2))).getText().toString();
                int n1=Integer.parseInt(num1);
                int n2=Integer.parseInt(num2);
                int n3=n1+n2;
                TextView tv=(TextView)findViewById(R.id.tv3);
                tv.setText("结果为："+n3);

            }
        });
        //-
        findViewById(R.id.btn2).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String num1=((EditText)(findViewById(R.id.et1))).getText().toString();
                String num2=((EditText)(findViewById(R.id.et2))).getText().toString();
                int n1=Integer.parseInt(num1);
                int n2=Integer.parseInt(num2);
                int n3=n1-n2;
                TextView tv=(TextView)findViewById(R.id.tv3);
                tv.setText("结果为："+n3);

            }
        });
        //*
        findViewById(R.id.btn3).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String num1=((EditText)(findViewById(R.id.et1))).getText().toString();
                String num2=((EditText)(findViewById(R.id.et2))).getText().toString();
                int n1=Integer.parseInt(num1);
                int n2=Integer.parseInt(num2);
                int n3=n1*n2;
                TextView tv=(TextView)findViewById(R.id.tv3);
                tv.setText("结果为："+n3);

            }
        });
        ///
        findViewById(R.id.btn4).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String num1=((EditText)(findViewById(R.id.et1))).getText().toString();
                String num2=((EditText)(findViewById(R.id.et2))).getText().toString();
                int n1=Integer.parseInt(num1);
                int n2=Integer.parseInt(num2);
                int n3=n1/n2;
                TextView tv=(TextView)findViewById(R.id.tv3);
                tv.setText("结果为："+n3);

            }
        });
    }
}