安卓第七周作业

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

package com.example.wyn;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

    Button btn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn=(Button) findViewById(R.id.btn1);
        btn.setOnClickListener(new OnClickListener() {
            
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent i = new Intent(MainActivity.this,MainActivity2.class);
                startActivity(i);
            }
        });
    }
        


  
    
}




package com.example.wyn;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity2 extends Activity {

    Button btn1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_activity2);
         btn1=(Button) findViewById(R.id.btn2);
            btn1.setOnClickListener(new OnClickListener() {
                
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    Intent i = new Intent();
                    i.setAction("cn.itcast.startactivity");
                    i.addCategory("android.intent.category.DEFAULT");
                    startActivity(i);
                }
            });
        
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main_activity2, menu);
        return true;
    }

}



package com.example.wyn;

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

public class MainActivity3 extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_activity3);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main_activity3, menu);
        return true;
    }

}

<LinearLayout 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=".MainActivity" >

    <Button
        android:id="@+id/btn1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         />
      <TextView 
         android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="1"/>
    

</LinearLayout>



<LinearLayout 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=".MainActivity2" >

    <Button
        android:id="@+id/btn2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         />
    <TextView 
         android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="2"/>

</LinearLayout>



<LinearLayout 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=".MainActivity3" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />
    <TextView 
         android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="3"/>

</LinearLayout>

 

 

2.在界面1做一个按钮开启浏览器访问百度

package com.example.wyn;

import android.net.Uri;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

    Button btn;
    Button btn2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn=(Button) findViewById(R.id.btn1);
        btn.setOnClickListener(new OnClickListener() {
            
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent i = new Intent(MainActivity.this,MainActivity2.class);
                startActivity(i);
            }
        });
        btn2=(Button) findViewById(R.id.btnllq);
        btn2.setOnClickListener(new OnClickListener() {
            
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent i = new Intent();
                i.setAction("android.intent.action.VIEW");
                i.setData(Uri.parse("http://www.baidu.com"));
                startActivity(i);
            }
        });
    }
        


  
    
}

 

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

package com.example.aswork1;

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity3 extends AppCompatActivity {
    EditText et1;
    EditText et2;
    Button btn1;
    Button btn2;
    Button btn3;
    Button btn4;
    TextView tv1;
    String str1;
    String str2;
    int a;
    int b;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main3);
        et1=findViewById(R.id.et1);
        et2=findViewById(R.id.et2);
        btn1=findViewById(R.id.btn1);
        btn2=findViewById(R.id.btn2);
        btn3=findViewById(R.id.btn3);
        btn4=findViewById(R.id.btn4);
        tv1=findViewById(R.id.tv1);
        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                str1=et1.getText().toString();
                str2=et2.getText().toString();
                a=Integer.parseInt(str1);
                b=Integer.parseInt(str2);
                String str3=""+(a+b);

                tv1.setText(str3);
            }
        });
        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                str1=et1.getText().toString();
                str2=et2.getText().toString();
                a=Integer.parseInt(str1);
                b=Integer.parseInt(str2);
                String str3=""+(a-b);

                tv1.setText(str3);
            }
        });
        btn3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                str1=et1.getText().toString();
                str2=et2.getText().toString();
                a=Integer.parseInt(str1);
                b=Integer.parseInt(str2);
                String str3=""+(a*b);

                tv1.setText(str3);
            }
        });
        btn4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                str1=et1.getText().toString();
                str2=et2.getText().toString();
                a=Integer.parseInt(str1);
                b=Integer.parseInt(str2);
                String str3=""+(a/b);

                tv1.setText(str3);
            }
        });

    }
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/rl_1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity3"
    android:orientation="vertical">

    <EditText
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:id="@+id/et1"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:id="@+id/et2"/>
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/btn1"
        android:text="加"/>
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/btn2"
        android:text="减"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/btn3"
        android:text="乘"/>
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/btn4"
        android:text="除"/>
    <TextView
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:id="@+id/tv1"/>




</LinearLayout>