安卓第七周

2021-10-07 18:02:01 作者：互联网

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

package com.example.app6;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;

public class Activity3 extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_activity3);
    }



}

package com.example.lj;

import android.net.Uri;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.util.Log;
import android.view.Menu;
import android.view.View;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.e("MainActivity", "调用oncreate");
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package com.example.lj;

import android.app.Activity;
import android.os.Bundle;

public class SecondActivity extends Activity {
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
    }

}
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<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".Activity2" >
    <Button 
        android:id="@+id/bt2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="开启界面三"
        />
</RelativeLayout>
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<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.app6"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.app6.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="com.example.app6.Activity2"
            android:label="@string/title_activity_activity2" >
        </activity>
        <activity
            android:name="com.example.app6.Activity3"
            android:label="@string/title_activity_activity3" >
            
              <intent-filter>
                <action android:name="com.lrp.start" />

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

</manifest>
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    }
   
    @Override
    protected void onStart() {
        // TODO Auto-generated method stub
        super.onStart();
        Log.e("MainActivity", "调用onstart");
    }
    @Override
    protected void onResume() {
        // TODO Auto-generated method stub
        super.onResume();
        Log.e("MainActivity", "调用onresume");
    }
    @Override
    protected void onPause() {
        // TODO Auto-generated method stub
        super.onPause();
        Log.e("MainActivity", "调用onpause");
    }
    
    @Override
    protected void onStop() {
        // TODO Auto-generated method stub
        super.onStop();
        Log.e("MainActivity", "调用onstop");
    }
    
    @Override
    protected void onDestroy() {
        // TODO Auto-generated method stub
        super.onDestroy();
        Log.e("MainActivity", "调用ondestroy");
    }
    
    @Override
    protected void onRestart() {
        // TODO Auto-generated method stub
        super.onRestart();
        Log.e("MainActivity", "调用onRestart");
    }
   
    public void click1(View view){
        Intent intent=new Intent(this,SecondActivity.class);
        startActivity(intent);
        
    }
   
    public void click2(View view){
        Intent intent=new Intent();
        intent.setAction("com.gd.activity2");
        intent.addCategory("android.intent.category.DEFAULT");
        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);
        
    }
    public void click4(View view){
        Intent intent=new Intent();
        intent.setAction("android.intent.action.VIEW");
        intent.setData(Uri.parse("tel:123456"));
        startActivity(intent);
        
    }
    
    public void click5(View view){
        Intent intent=new Intent();
        intent.setAction("android.media.action.IMAGE_CAPTURE");
        intent.addCategory("android.intent.category.DEFAULT");
        startActivity(intent);
        
    }


    
}

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

RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >
 
    <EditText
        android:id="@+id/et1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="请输入第一个数"
        android:textSize="50dp"
        android:background="#32FF00"
        android:layout_marginBottom="100dp"
        />
 
    <EditText
        android:id="@+id/et2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="请输入第二个数"
        android:textSize="50dp"
        android:background="#00FFF6"
        android:layout_below="@id/et1"
        android:layout_marginBottom="100dp"
        />
    <Button
        android:layout_below="@id/et2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/b1"
        android:text="+"
        android:textSize="50dp"
        android:textColor="#FF0000"
 
        />
    <Button
        android:layout_below="@id/et2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/b2"
        android:text="-"
        android:textSize="50dp"
        android:layout_toRightOf="@id/b1"
        />
    <Button
        android:layout_below="@id/et2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/b3"
        android:text="*"
        android:textSize="50dp"
        android:layout_toRightOf="@id/b2"
        />
    <Button
        android:layout_below="@id/et2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/b4"
        android:textSize="50dp"
        android:text="/"
        android:layout_toRightOf="@id/b3"
        />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/tv"
        android:layout_below="@id/b1"
        android:text="结果是"
        android:textSize="50dp"
        />
 
 
</RelativeLayout>
package com.example.mya;

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 ThreeActivity extends AppCompatActivity {

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

        //加法运算
        findViewById(R.id.C1).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String num1=((EditText)(findViewById(R.id.B1))).getText().toString();
                String num2=((EditText)(findViewById(R.id.B2))).getText().toString();
                int n1=Integer.parseInt(num1);
                int n2=Integer.parseInt(num2);
                int n3=n1+n2;
                TextView jieguo=(TextView)findViewById(R.id.A2);
                jieguo.setText("计算结果是："+n3);
            }
        });

        //减法运算
        findViewById(R.id.C2).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String num1=((EditText)(findViewById(R.id.B1))).getText().toString();
                String num2=((EditText)(findViewById(R.id.B2))).getText().toString();
                int n1=Integer.parseInt(num1);
                int n2=Integer.parseInt(num2);
                int n3=n1-n2;
                TextView jieguo=(TextView)findViewById(R.id.A2);
                jieguo.setText("计算结果是："+n3);
            }
        });

        //乘法运算
        findViewById(R.id.C3).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String num1=((EditText)(findViewById(R.id.B1))).getText().toString();
                String num2=((EditText)(findViewById(R.id.B2))).getText().toString();
                int n1=Integer.parseInt(num1);
                int n2=Integer.parseInt(num2);
                int n3=n1*n2;
                TextView jieguo=(TextView)findViewById(R.id.A2);
                jieguo.setText("计算结果是："+n3);
            }
        });

        //除法运算
        findViewById(R.id.C4).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String num1=((EditText)(findViewById(R.id.B1))).getText().toString();
                String num2=((EditText)(findViewById(R.id.B2))).getText().toString();
                int n1=Integer.parseInt(num1);
                int n2=Integer.parseInt(num2);
                int n3=n1/n2;
                TextView jieguo=(TextView)findViewById(R.id.A2);
                jieguo.setText("计算结果是："+n3);
            }
        });

    }

}
 package com.example.myapplication;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
 
public class MainActivity extends Activity {
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
//        +
        findViewById(R.id.b1).setOnClickListener(new View.OnClickListener() {
 
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                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 tv1=(TextView)findViewById(R.id.tv);
                tv1.setText("结果是"+n3);
            }
        });
//        -
        findViewById(R.id.b2).setOnClickListener(new View.OnClickListener() {
 
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                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 tv1=(TextView)findViewById(R.id.tv);
                tv1.setText("结果是"+n3);
            }
        });
 
//        *
        findViewById(R.id.b3).setOnClickListener(new View.OnClickListener() {
 
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                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 tv1=(TextView)findViewById(R.id.tv);
                tv1.setText("结果是"+n3);
            }
        });
 
//        /
        findViewById(R.id.b4).setOnClickListener(new View.OnClickListener() {
 
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                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 tv1=(TextView)findViewById(R.id.tv);
                tv1.setText("结果是"+n3);
            }
        });
    }
 
 
}

标签：findViewById,第七,int,void,id,import,android,安卓
来源： https://www.cnblogs.com/leopard1/p/15376585.html