（一）Activity参数传递-白红宇

（一）Activity参数传递

阅读量：5323 次

发布时间：2019-06-14

本文共 11485 字，大约阅读时间需要 38 分钟。

1.主Activity,用于启动另一个Activity（） public class MainActivity extends Activity {    @Override     protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         System.out.println("onCreate");         findViewById(R.id.btnStartBAct).setOnClickListener(new View.OnClickListener() {
              @Override             public void onClick(View view) {
                  Intent intent=new Intent(MainActivity.this,BActivity.class);  intent.putExtra("data","Hello Henry");                                  //进行参数传递                 //startActivity(new Intent(MainActivity.this,BActivity.class));                 startActivity(intent);             }         });     }     @Override     protected void onStart()     {
          super.onStart();         System.out.println("onStrart");     }     @Override     protected void onRestart()     {
          super.onRestart();         System.out.println("onRestart");     }     @Override     protected void onStop()     {
          super.onStart();         System.out.println("onStop");     }     @Override     protected void onResume()     {
          super.onResume();         System.out.println("onResume");     }     @Override     protected void onPause()     {
          super.onPause();         System.out.println("onPause");     }     @Override     protected void onDestroy()     {
          super.onDestroy();         System.out.println("onDestroy");     }     @Override     public boolean onCreateOptionsMenu(Menu menu) {
          // Inflate the menu; this adds items to the action bar if it is present.         getMenuInflater().inflate(R.menu.menu_main, menu);         return true;     }     @Override     public boolean onOptionsItemSelected(MenuItem item) {
          // Handle action bar item clicks here. The action bar will         // automatically handle clicks on the Home/Up button, so long         // as you specify a parent activity in AndroidManifest.xml.         int id = item.getItemId();         //noinspection SimplifiableIfStatement         if (id == R.id.action_settings) {
              return true;         }         return super.onOptionsItemSelected(item);     } } 2.从Activity 被MainActivity启动

public class BActivity extends Activity {
      @Override     protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);         setContentView(R.layout.activity_b);         System.out.println("B onCreate");    Intent intent=getIntent();              //获取MainActivity传递过来的Intent         TextView tv= (TextView) findViewById(R.id.tv);           tv.setText(intent.getStringExtra("data"));           //调用Intent的getStringExtra("data")方法取出数据

}     @Override     protected void onStart()     {
          super.onStart();         System.out.println("B onStrart");     }     @Override     protected void onRestart()     {
          super.onRestart();         System.out.println("B onRestart");     }     @Override     protected void onStop()     {
          super.onStart();         System.out.println("B onStop");     }     @Override     protected void onResume()     {
          super.onResume();         System.out.println("B onResume");     }     @Override     protected void onPause()     {
          super.onPause();         System.out.println("B onPause");     }     @Override     protected void onDestroy()     {
          super.onDestroy();         System.out.println("B onDestroy");     }     @Override     public boolean onCreateOptionsMenu(Menu menu) {
          // Inflate the menu; this adds items to the action bar if it is present.         getMenuInflater().inflate(R.menu.menu_b, menu);         return true;     }     @Override     public boolean onOptionsItemSelected(MenuItem item) {
          // Handle action bar item clicks here. The action bar will         // automatically handle clicks on the Home/Up button, so long         // as you specify a parent activity in AndroidManifest.xml.         int id = item.getItemId();         //noinspection SimplifiableIfStatement         if (id == R.id.action_settings) {
              return true;         }         return super.onOptionsItemSelected(item);     } } 3.传递数据包Bundle 3.1 MainActivity中的 findViewById(R.id.btnStartBAct).setOnClickListener(new View.OnClickListener() {

@Override         public void onClick(View view) {
               Intent intent=new Intent(MainActivity.this,BActivity.class);             //intent.putExtra("data","Hello Henry");             //传递数据包     Bundle bundle=new Bundle();             bundle.putString("name","henry");       //往数据包中添加数据             bundle.putInt("age",24);             intent.putExtras(bundle);               //将数据包添加到Intent中             //startActivity(new Intent(MainActivity.this,BActivity.class));             startActivity(intent);         }     }); } 3.2  BActivity中的

Intent intent=getIntent(); Bundle bundle=intent.getExtras();        //接收数据包 TextView tv= (TextView) findViewById(R.id.tv); //tv.setText(intent.getStringExtra("data")); tv.setText(String.format("name=%s,age=%d",bundle.getString("name"),(int)bundle.get("age")));    //调用Bundle的getXXX（）函数获取数据

4.传递引用 4.1使用序列化的方式传递引用类 自定义类：

public class User implements Serializable {        //使用java提供的序列化的方式       private String name;     private int age;     public void setName(String name) {
          this.name = name;     }     public void setAge(int age) {
          this.age = age;     }     public String getName() {
          return name;     }     public int getAge() {
          return age;     }     public User(String name,int age)     {
          this.name=name;         this.age=age;     } } 主Activity：

public class MainActivity extends Activity {
      @Override     protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         findViewById(R.id.btnStartBAct).setOnClickListener(new View.OnClickListener() {
              @Override             public void onClick(View view) {
                  Intent intent=new Intent(MainActivity.this,BActivity.class);             intent.putExtra("user", (Serializable) new User("henryQL",24));      //添加自定义的引用类的对象                 startActivity(intent);             }         });     }   } 被调用的Activity：

public class BActivity extends Activity {
      @Override     protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);         setContentView(R.layout.activity_b);          Intent intent=getIntent();        User user= (User) intent.getSerializableExtra("user");    //获取序列化的数据         TextView tv= (TextView) findViewById(R.id.tv);               tv.setText(String.format("nmae=%s,age=%d",user.getName(),user.getAge()));     } } 4.2 使用Android提供的Parcelable接口

public class User implements Parcelable {
      private String name;     private int age;     public void setName(String name) {
          this.name = name;     }     public void setAge(int age) {
          this.age = age;     }     public String getName() {
          return name;     }     public int getAge() {
          return age;     }     public User(String name,int age)     {
          this.name=name;         this.age=age;     }     @Override     public int describeContents() {
          return 0;     }     @Override     public void writeToParcel(Parcel parcel, int i) {
          parcel.writeString(getName());         parcel.writeInt(getAge());     }     public static final Parcelable.Creator
    
      CREATOR=new Parcelable.Creator
     
      ()    //必须命名为CREATOR     {
          @Override         public User createFromParcel(Parcel parcel) {
              return new User(parcel.readString(),parcel.readInt());         }         @Override         public User[] newArray(int i) {
              return new User[i];         }     }; }

public class MainActivity extends Activity {
      @Override     protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         System.out.println("onCreate");         findViewById(R.id.btnStartBAct).setOnClickListener(new View.OnClickListener() {
              @Override             public void onClick(View view) {
                  Intent intent=new Intent(MainActivity.this,BActivity.class);                   intent.putExtra("user",new User("Qianlong",24));                 //startActivity(new Intent(MainActivity.this,BActivity.class));                 startActivity(intent);             }         });     } }

public class BActivity extends Activity {
      @Override     protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);         setContentView(R.layout.activity_b);         System.out.println("B onCreate");         Intent intent=getIntent();        User user=intent.getParcelableExtra("user");      //获取Parcelable对象         TextView tv= (TextView) findViewById(R.id.tv);         //tv.setText(intent.getStringExtra("data"));         //tv.setText(String.format("name=%s,age=%d",bundle.getString("name"),(int)bundle.get("age")));         tv.setText(String.format("nmae=%s,age=%d",user.getName(),user.getAge()));     } } 5.Activity传递返回参数 若想打开一个新的Activity的时候能够获取其返回的参数，必须使用startActivityForResult，而不能是之前的startActivity函数了； 此外必须在该类中重写函数onActivityResult，在该函数中用来响应返回的数据。在新的Activity中使用setRequest来发送要返回的数据，并使用finish函数来结束当前的Activity。

public class MainActivity extends Activity {
      private TextView rtnTextView;     @Override     protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         rtnTextView= (TextView) findViewById(R.id.rtnTextView);         findViewById(R.id.newActivityBtn).setOnClickListener(new View.OnClickListener() {
              @Override             public void onClick(View view) {
                  //发送数据，并且能够获取另一activity的返回数据                 Intent intent=new Intent(MainActivity.this,MainActivity2Activity.class);                 intent.putExtra("name","henry");                 intent.putExtra("age",24);  startActivityForResult(intent,1);   //第二个参数是请求码，设置请求码和要发送的intent数据             }         });     }     //响应MainActivity2Activity的返回数据     @Override     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
           super.onActivityResult(requestCode, resultCode, data);         rtnTextView.setText(data.getStringExtra("data"));   //获取返回的数据     } }

public class MainActivity2Activity extends Activity {
      @Override     protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main_activity2);         TextView tv=(TextView)findViewById(R.id.displayTextView);         Intent intent=getIntent();         tv.setText(String.format("name=%s,age=%d",intent.getStringExtra("name"),intent.getIntExtra("age",0)));         //传递返回值         final EditText editText=(EditText)findViewById(R.id.editText);         findViewById(R.id.returnBtn).setOnClickListener(new View.OnClickListener() {
              @Override             public void onClick(View view) {
     Intent intent1=new Intent();                 intent1.putExtra("data",editText.getText().toString());                 setResult(1,intent1);   //设置返回码，和要返回的Intent                 finish();                            }         });     } }

转载于:https://www.cnblogs.com/ql698214/p/5071371.html

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