Android的四大组件:Activity,BroadcastReceiver,Service,ContentProvider
(一)Activity
1.效果图:点击开启第二个Activity 显示到第二个页面
2.布局: 两个布局
activity_main.xml
1 <?xml version="1.0" encoding="utf-8"?> 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 3 xmlns:tools="http://schemas.android.com/tools" 4 android:layout_width="match_parent" 5 android:layout_height="match_parent" 6 android:paddingBottom="@dimen/activity_vertical_margin" 7 android:paddingLeft="@dimen/activity_horizontal_margin" 8 android:paddingRight="@dimen/activity_horizontal_margin" 9 android:paddingTop="@dimen/activity_vertical_margin" 10 tools:context="com.example.app2.MainActivity" 11 android:orientation="vertical"> 12 13 <Button 14 android:id="@+id/btn_open" 15 android:layout_width="match_parent" 16 android:layout_height="wrap_content" 17 android:text="开启第二个 Activity " /> 18 </LinearLayout>
slayout
1 <?xml version="1.0" encoding="utf-8"?> 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 3 android:layout_width="match_parent" 4 android:layout_height="match_parent" 5 android:orientation="vertical"> 6 <TextView 7 android:id="@+id/tv" 8 android:textColor="@color/colorAccent" 9 android:textSize="30dp" 10 android:layout_width="match_parent" 11 android:layout_height="wrap_content" /> 12 <Button 13 android:id="@+id/btn_close" 14 android:text="关闭当前Activity" 15 android:layout_width="match_parent" 16 android:layout_height="wrap_content" /> 17 18 </LinearLayout>
3.注册
<activity android:name=".SActivity"></activity>
4.
MainActivity.java
1 package com.example.app2; 2 3 import android.content.Intent; 4 import android.support.v7.app.AppCompatActivity; 5 import android.os.Bundle; 6 import android.view.View; 7 import android.widget.Button; 8 import android.widget.Toast; 9 10 public class MainActivity extends AppCompatActivity { 11 private Button button; 12 13 @Override 14 protected void onCreate(Bundle savedInstanceState) { 15 super.onCreate(savedInstanceState); 16 setContentView(R.layout.activity_main); 17 button = (Button) findViewById(R.id.btn_open); 18 final Intent intent = new Intent(MainActivity.this,SActivity.class); 19 button.setOnClickListener(new View.OnClickListener() { 20 @Override 21 public void onClick(View v) { 22 intent.putExtra("info","second Activity"); 23 startActivity(intent); 24 } 25 }); 26 } 27 }
SActivity.java
1 package com.example.app2; 2 3 import android.app.Activity; 4 import android.content.Intent; 5 import android.os.Bundle; 6 import android.view.View; 7 import android.widget.Button; 8 import android.widget.TextView; 9 10 /** 11 * Created by Administrator on 2018/5/22. 12 */ 13 public class SActivity extends Activity { 14 private Button button_close; 15 private TextView textView; 16 17 @Override 18 protected void onCreate(Bundle savedInstanceState) { 19 super.onCreate(savedInstanceState); 20 setContentView(R.layout.slayout); 21 textView = (TextView)findViewById(R.id.tv); 22 button_close = (Button)findViewById(R.id.btn_close); 23 Intent intent = getIntent(); 24 String info = intent.getStringExtra("info"); 25 textView.setText(info); 26 button_close.setOnClickListener(new View.OnClickListener() { 27 @Override 28 public void onClick(View v) { 29 30 finish(); 31 32 } 33 }); 34 35 } 36 }