安卓学习UI组件-Activity-组件-白红宇

安卓学习UI组件-Activity-组件

阅读量：7092 次

发布时间：2019-06-28

本文共 14453 字，大约阅读时间需要 48 分钟。

1.Activity概述

2.状态与生命周期概述

3.状态与生命周期详解

package com.example.administrator.myapplication; import android.app.Activity; import android.os.Bundle; /*Activity三个状态和七大生命周期方法分析*/ public class MainActivity extends Activity {
        //activity创建时第一个调用的方法，通常我们在该方法中加载布局文件，初始化UI组件，事件注册等等     @Override     protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         System.out.println("MainActivity-onCreate");     }     /*在onCreate之后调用，用于显示界面，但用户还不能进行交互*/     @Override     protected void onStart() {
            super.onStart();         System.out.println("MainActivity-onStart");     } /*当一个stopped状态的Activity被返回时调用，之后再调用onStart)方法，进入运行状态*/     @Override     protected void onRestart() {
            super.onRestart();         System.out.println("MainActivity-onRestart");     }     /*在onStart后调用，该方法执行完成后，用户可以进行交互，当前Activity进入resume的状态（运行状态）     * 当一个paused状态的activity被重新返回时，会再次调用该方法，让Activity进入运行状态     * */     @Override     protected void onResume() {
            super.onResume();         System.out.println("MainActivity-onResume");     }     /*当其他Activity（透明或窗口模式）进入时，该方法被调用，让当前Activity进入paused（暂停）状态     * 当前Activity还可见，但不可进行交互，如果其他更高优先级的APP需要内存时，当前Activity可能会被销毁（kill）     * 当前Activity被返回时会调用onResume（）方法     * */     @Override     protected void onPause() {
            super.onPause();         System.out.println("MainActivity-onPause");     }     /*当其他Activity完全覆盖该Activity时，会被调用，当前Activity进入stopped状态（停止状态）     * 当前Activity不可见，不可进行交互，如果其他更高优先级的APP需要内存时，当前Activity可能会被销毁（kill）     * 当前Activity被返回时会调用onRestart（）方法     * */     @Override     protected void onStop() {
            super.onStop();         System.out.println("MainActivity-onStop");     }     /*当前Activity被销毁时调用，通常在该方法中用来释放资源，当前Activity killed*/     @Override     protected void onDestroy() {
            super.onDestroy();         System.out.println("MainActivity-onDestroy");     } }

4.传递简单数据

Dog.java

package com.example.administrator.myapplication; import android.os.Parcel; import android.os.Parcelable; /**  * Created by Administrator on 2016/3/17.  */ //打包裹 传递对象 性能好 public class Dog implements Parcelable{
        String name;     int age;     String type;     @Override     public String toString() {
            return "Dog{" +                 "age=" + age +                 ", name='" + name + '\'' +                 ", type='" + type + '\'' +                 '}';     }     //描述内容     @Override     public int describeContents() {
            return 0;     }     @Override     public void writeToParcel(Parcel dest, int flags) {
    //把传递数据写进dest         dest.writeString(name);         dest.writeInt(age);         dest.writeString(type);     } //对象的创建器 序列化包裹     public static final Parcelable.Creator
     
       CREATOR             =new Parcelable.Creator
      
       ()     {
            @Override         public Dog createFromParcel(Parcel in) {
                Dog dog=new Dog();             dog.name=in.readString();             dog.age=in.readInt();             dog.type=in.readString();             return dog;         }         @Override         public Dog[] newArray(int size) {
                return new Dog[size];         }     }; }

cat.java

package com.example.administrator.myapplication; import java.io.Serializable; /**  * Created by Administrator on 2016/3/17.  */ //可序列化 IO序列化 性能比较低 public class Cat implements Serializable {
        String name;     int age;     String type;     @Override     public String toString() {
            return "Cat{" +                 "age=" + age +                 ", name='" + name + '\'' +                 ", type='" + type + '\'' +                 '}';     } }

activity_main_a.xml

MainActivityA.java

package com.example.administrator.myapplication; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.EditText; public class MainActivityA extends Activity {
        private EditText editText_info;     @Override     protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main_a);         editText_info = (EditText) findViewById(R.id.editText_info);     }     /*启动ActivityB，并且要传递数据*/     public void sendClick(View v) {
            //创建一个意图（想干什么） 参数：上下文，要跳转的组件的字节码         Intent intent = new Intent(this, MainActivityB.class);         String info = editText_info.getText().toString();         //封装要传递的数据，第一种方法        /* Bundle data = new Bundle();         data.putString("info", info);         intent.putExtra("data",data);*/         //第二种方法         intent.putExtra("info", info);         intent.putExtra("age", 24);         startActivity(intent);     }     public void sendObjClick(View v) {
            //用IO消耗的性能比较多         //要传递的对象         Cat cat = new Cat();         cat.name = "皮卡丘";         cat.age = 2;         cat.type = "英短";         Intent intent = new Intent(this, MainActivityB.class);         intent.putExtra("cat", cat);         startActivity(intent);     }     public void sendObj2Click(View v) {
            //Parcelable         Dog dog = new Dog();         dog.name="旺旺";         dog.age=1;         dog.type="金毛";         Intent intent = new Intent(this, MainActivityB.class);         intent.putExtra("dog",dog);         startActivity(intent);     } }

activity_main_b.xml

MainActivityB.java

package com.example.administrator.myapplication; import android.content.Intent; import android.support.v7.app.ActionBarActivity; import android.os.Bundle; import android.widget.TextView; public class MainActivityB extends ActionBarActivity {
        private TextView textView_info;     @Override     protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main_b);         textView_info = (TextView) findViewById(R.id.info);         //intent内容一样 不是一个intent         Intent intent = getIntent();         //第一种        /* Bundle data = intent.getBundleExtra("data");         String info = data.getString("info");         textView_info.setText(info);*/         //第二种         String info = intent.getStringExtra("info");         //第二个参数为默认值         int age = intent.getIntExtra("age", 18);         Cat cat = (Cat) intent.getSerializableExtra("cat");       //  Dog dog = intent.getParcelableExtra("dog");       //  textView_info.setText(info + "---" + age );        textView_info.setText(info + "---" + age + "--" + cat.toString()+"\n");        // textView_info.setText(dog.toString());     } }

5.传递自定义对象数据

6.处理返回结果

activity_main_activity_result.xml

MainActivityResult.java

package com.example.administrator.myapplication; import android.content.Intent; import android.net.Uri; import android.support.v7.app.ActionBarActivity; import android.os.Bundle; import android.view.View; import android.widget.EditText; public class MainActivityResult extends ActionBarActivity {
        private static final int REQUESTCODE_1 = 0x1;     private EditText editText_number;     @Override     protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main_activity_result);         editText_number = (EditText) findViewById(R.id.editText_number);     }     /*选择一个电话号码*/     public void selectClick(View v) {
            Intent intent = new Intent(this, PhoneNumberListActivity.class);         //返回结果 第一个参数 intent 第二个参数 请求编码         startActivityForResult(intent, REQUESTCODE_1);     }     //重写该方法来处理返回的结果     @Override     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);         if (requestCode == REQUESTCODE_1 && resultCode == RESULT_OK) {
                String number = data.getStringExtra("number");             editText_number.setText(number);         }     }     /*拨打电话*/     public void callClick(View v) {
            String number=editText_number.getText().toString();         Intent intent=new Intent();         intent.setAction(Intent.ACTION_CALL);         intent.setData(Uri.parse("tel:"+number));         startActivity(intent);     } }

activity_phone_number_list.xml

PhoneNumberListActivity.java

package com.example.administrator.myapplication; import android.content.Intent; import android.support.v7.app.ActionBarActivity; import android.os.Bundle; import android.view.View; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.ListView; public class PhoneNumberListActivity extends ActionBarActivity {
        private ListView listView;     @Override     protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);         setContentView(R.layout.activity_phone_number_list);         listView= (ListView) findViewById(R.id.listView);         final String[] numbers={"13713820115","13692208307","13760359165","15817447169","13713686009"};         ArrayAdapter
     
       adapter=new ArrayAdapter
      
                        (this,android.R.layout.simple_list_item_1,android.R.id.text1,numbers);         listView.setAdapter(adapter);         listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override             public void onItemClick(AdapterView
        parent, View view, int position, long id) {
                    String number=numbers[position];                 Intent intent=new Intent();                 intent.putExtra("number",number);                 setResult(RESULT_OK,intent);//设置返回结果                 finish();//结束当前界面             }         });     } }

//最后要在清单文件配置打电话权限

7.屏幕方向与显示方式

横屏android:screenOrientation="landscape"

竖屏android:screenOrientation="portrait"

设置主题全屏 android:theme="@android:style/Theme.DeviceDefault.NoActionBar.Fullscreen"

activity_screen_orientation.xml

ScreamOrientationActivity.java

package com.example.administrator.myapplication; import android.app.Activity; import android.content.pm.ActivityInfo; import android.os.Bundle; import android.view.Window; import android.view.WindowManager; /*设置全屏模式 * 1.通过代码实现 * 2.在清单文件中可以通过设置Activity的主题： * android:theme="@android:style/Theme.DeviceDefault.NoActionBar.Fullscreen" * * 设置窗体模式 * 1.在清单文件中设置主题： * android:theme="@android:style/Theme.DeviceDefault.Dialog" * */ public class ScreamOrientationActivity extends Activity {
        @Override     protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);         //通过代码设置屏幕方向       //  setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);         //  setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);       //设置全屏       //  getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);   //去除标题栏        // requestWindowFeature(Window.FEATURE_NO_TITLE);         setContentView(R.layout.activity_scream_orientation);     } }

8.屏幕方向旋转

android:configChanges="keyboard|orientation|screenSize"

当配置了android:configChanges="orientation"属性，在横紧屏切换的时候不会重新执行Activity的onCreate方法，只是执行onConfigurationChanged方法，否则切换的时候会重新执行onCreate方法

activity_screen_change.xml

竖屏文件放在layout-land目录

ScreenChangeActivity.java

package com.example.administrator.myapplication; import android.app.Activity; import android.content.res.Configuration; import android.support.v7.app.ActionBarActivity; import android.os.Bundle; import android.view.View; /*屏幕切换默认情况下会重新创建Activity * 为了保存当前Activity的状态，我们可以重写onSaveInstanceState方法来保存相关数据 * 然后在onCreate方法中还原数据*/ public class ScreenChangeActivity extends Activity {
        int index = 0;     //横屏竖屏状态要保存下来     @Override     protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);         setContentView(R.layout.activity_screen_change);         System.out.println("ScreenChangeActivity--onCreate"); //还原状态值         if (savedInstanceState != null) {
                index = savedInstanceState.getInt("index", 0);         }     }     public void changeClick(View v) {
            index++;         System.out.println("index=" + index);     }     //切换屏保存状态     @Override     protected void onSaveInstanceState(Bundle outState) {
            super.onSaveInstanceState(outState);         System.out.println("onSaveInstanceState");         outState.putInt("index", index);     }     //改变布局排版配置     @Override     public void onConfigurationChanged(Configuration newConfig) {
            super.onConfigurationChanged(newConfig);         System.out.println("onConfigurationChanged");     } }

AndroidManifest.xml

9.SharedPreferences

activity_share_preferences.xml

SharePreferencesActivity.java

package com.example.administrator.myapplication; import android.content.Context; import android.content.SharedPreferences; import android.support.v7.app.ActionBarActivity; import android.os.Bundle; import android.text.TextUtils; import android.widget.EditText; public class SharePreferencesActivity extends ActionBarActivity {
       private SharedPreferences sp;   private EditText editText_msg;     @Override     protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);         setContentView(R.layout.activity_share_preferences);  editText_msg= (EditText) findViewById(R.id.editText_msg);         //获取当前程序的SharedPreferences对象         sp = getSharedPreferences("msg", Context.MODE_PRIVATE);     }     //还原数据     @Override     protected void onResume() {
           super.onResume();         editText_msg.setText(sp.getString("msg", ""));         //删除数据       SharedPreferences.Editor editor=sp.edit();         editor.remove("msg");         editor.commit();     }     //我们在该事件方法里来存储数据     @Override     protected void onPause() {
           super.onPause();         String msg=editText_msg.getText().toString();         if(TextUtils.isEmpty(msg))         {
               return;         }        SharedPreferences.Editor editor= sp.edit();         editor.putString("msg",msg);         editor.commit();//提交     } }