1.
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <Button android:id="@+id/B_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="显式意图开启页面2"/>
<Button android:id="@+id/bt_2" android:layout_below="@id/bt_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="隐式意图开启界面3"/>
</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=".Main2Activity"> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="20dp" android:text="界面2"/> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="20dp" android:text="界面3"/>
</LinearLayout>
package com.example.h1; 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); } }); } package com.example.h2; 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.zqj.second"); startActivity(intent); } }); } }
2
<?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=".MainActivity" android:orientation="vertical"> <Button android:id="@+id/bt_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="开启访问百度" android:textSize="30dp" android:onClick="click1" /> </LinearLayout> package="com.example.myapplication3"> <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=".ThirdActivity"> <intent-filter> <action android:name="com.example.start" /> <category android:name="android.intent.category.DEFAULT" /> </intent-filter> </activity> <activity android:name=".SecondActivity" > </activity> <activity android:name=".IntentActivity" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name=".ButtonActivity"> </activity> <activity android:name=".MainActivity" /> </application> </manifest>
3.
<?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" tools:context=".Main2Activity" android:layout_margin="20dp"> <TextView android:id="@+id/tv1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="数字:" android:textColor="#000000" android:textSize="20sp" android:layout_marginTop="15dp"/> <EditText android:id="@+id/et1" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="请输入数字" android:textSize="25sp" android:textColorHint="#E91313" android:maxLines="1" android:scrollHorizontally="true" android:layout_toRightOf="@+id/tv1"/> <TextView android:id="@+id/tv2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="数字:" android:textColor="#000000" android:textSize="20sp" android:layout_marginTop="25dp" android:layout_below="@id/tv1"/> <EditText android:id="@+id/et2" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="请输入数字" android:textSize="25sp" android:textColorHint="#E91313" android:maxLines="1" android:scrollHorizontally="true" android:layout_toRightOf="@+id/tv1" android:layout_below="@id/et1"/> <Button android:id="@+id/btn_1" android:layout_width="100dp" android:layout_height="100dp" android:text="+" android:textColor="#000000" android:textSize="50sp" android:layout_below="@id/et2" android:layout_marginTop="100dp" android:layout_margin="10dp" android:layout_alignLeft="@id/et2" /> <Button android:id="@+id/btn_2" android:layout_width="100dp" android:layout_height="100dp" android:text="-" android:textColor="#000000" android:textSize="50sp" android:layout_below="@id/et2" android:layout_toRightOf="@id/btn_1" /> <Button android:id="@+id/btn_3" android:layout_width="100dp" android:layout_height="100dp" android:layout_below="@id/btn_1" android:layout_margin="10dp" android:text="*" android:textColor="#000000" android:textSize="50sp" android:layout_alignLeft="@id/et2" /> <Button android:id="@+id/btn_4" android:layout_width="100dp" android:layout_height="100dp" android:layout_below="@id/btn_1" android:layout_toRightOf="@id/btn_3" android:text="/" android:textColor="#000000" android:textSize="50sp" android:layout_alignTop="@id/btn_3" /> <TextView android:id="@+id/tv3" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/btn_3" android:layout_margin="20dp" android:text="结果是:" android:textSize="45sp" android:textColor="#000000" android:textStyle="italic"/> </RelativeLayout>
package com.example.myapplication; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.EditText; import android.widget.TextView; public class Main2Activity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main2); //+ findViewById(R.id.btn_1).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 tv1=(TextView)findViewById(R.id.tv3); tv1.setText("结果是"+n3); } }); //- findViewById(R.id.btn_2).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 tv1=(TextView)findViewById(R.id.tv3); tv1.setText("结果是"+n3); } }); //* findViewById(R.id.btn_3).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 tv1=(TextView)findViewById(R.id.tv3); tv1.setText("结果是"+n3); } }); //除 findViewById(R.id.btn_4).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 tv1=(TextView)findViewById(R.id.tv3); tv1.setText("结果是"+n3); } }); } }