1.
<?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"> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="显式意图" android:layout_gravity="center" android:onClick="onClick"/> </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" android:orientation="vertical"> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="隐式意图" android:onClick="onClick" 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" android:orientation="vertical"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="第三个界面" android:textSize="100px" android:layout_gravity="center"/> </LinearLayout>
package com.example.work4_1; import androidx.appcompat.app.AppCompatActivity; import android.content.Intent; import android.view.View; import android.content.Intent; import android.os.Bundle; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } public void onClick(View v){ Intent intent = new Intent(MainActivity.this,SecondActivity.class); startActivity(intent); } }
import androidx.appcompat.app.AppCompatActivity; import android.content.Intent; import android.os.Bundle; import android.view.View; public class SecondActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_second); } public void onClick(View v){ Intent intent = new Intent(); intent.setAction("cn.itcast.START_ACTIVITY"); startActivity(intent); } }
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.work4_1"> <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="cn.itcast.START_ACTIVITY" /> <category android:name="android.intent.category.DEFAULT" /> <!-- <data--> <!-- android:mimeType="aa/bb"--> <!-- android:scheme="mytestscheme" />--> </intent-filter> </activity> <activity android:name=".SecondActivity"> <intent-filter> <action android:name="cn.itcast.SECOND_ACTIVITY" /> <category android:name="android.intent.category.DEFAULT" /> <!-- <data--> <!-- android:mimeType="aa/bb"--> <!-- android:scheme="mytestscheme" />--> </intent-filter> </activity> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
2.
import androidx.appcompat.app.AppCompatActivity; import android.content.Intent; import android.net.Uri; import android.view.View; import android.content.Intent; import android.os.Bundle; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } public void onClick(View v){ Intent intent= new Intent(); intent.setAction("android.intent.action.VIEW"); intent.setData(Uri.parse("http://www.baidu.com")); startActivity(intent); } } package com.example.work4_1; import androidx.appcompat.app.AppCompatActivity; import android.content.Intent; import android.net.Uri; import android.view.View; import android.content.Intent; import android.os.Bundle; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } public void onClick(View v){ Intent intent= new Intent(); intent.setAction("android.intent.action.VIEW"); intent.setData(Uri.parse("http://www.baidu.com")); startActivity(intent); } }
<?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"> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="打开百度" android:layout_gravity="center" android:onClick="onClick"/> </LinearLayout>
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=".MainActivity"> <EditText android:id="@+id/et1" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="50dp" android:gravity="center" android:textSize="50dp"/> <EditText android:id="@+id/et2" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="50dp" android:layout_below="@id/et1" android:gravity="center" android:textSize="50dp"/> <Button android:id="@+id/add" android:layout_width="200px" android:layout_height="200px" android:text="+" android:textSize="50dp" android:layout_below="@id/et2" android:layout_marginTop="80dp" android:onClick="add"/> <Button android:id="@+id/reduce" android:layout_width="200px" android:layout_height="200px" android:text="-" android:textSize="50dp" android:layout_below="@id/et2" android:layout_toRightOf="@id/add" android:layout_marginTop="80dp" android:layout_marginLeft="30dp" android:onClick="reduce"/> <Button android:id="@+id/ride" android:layout_width="200px" android:layout_height="200px" android:text="*" android:textSize="50dp" android:layout_below="@id/et2" android:layout_toLeftOf="@id/except" android:layout_marginTop="80dp" android:onClick="ride"/> <Button android:id="@+id/except" android:layout_width="200px" android:layout_height="200px" android:text="/" android:textSize="50dp" android:layout_below="@id/et2" android:layout_alignParentRight="true" android:layout_marginTop="80dp" android:layout_marginLeft="30dp" android:onClick="except"/> <!-- android:layout_toRightOf="@id/ride"--> <TextView android:id="@+id/tx1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="结果是:" android:textSize="50dp" android:layout_below="@id/add" android:layout_marginTop="80dp" /> <TextView android:id="@+id/tx2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="" android:textSize="50dp" android:layout_below="@id/add" android:layout_toRightOf="@id/tx1" android:layout_marginTop="80dp" /> </RelativeLayout>
import androidx.appcompat.app.AppCompatActivity; 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); } public void add(View v){ 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); TextView tx2=(TextView)findViewById(R.id.tx2); int sum = n1+n2; tx2.setText(String.valueOf(sum)); } public void reduce(View v){ 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); TextView tx2=(TextView)findViewById(R.id.tx2); int sum = n1-n2; tx2.setText(String.valueOf(sum)); } public void ride(View v){ 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); TextView tx2=(TextView)findViewById(R.id.tx2); int sum = n1*n2; tx2.setText(String.valueOf(sum)); } public void except(View v){ 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); TextView tx2=(TextView)findViewById(R.id.tx2); int sum = n1/n2; tx2.setText(String.valueOf(sum)); } }