Android 四大组件之（1）Activity与Intent通信机制

1、使用Intent对象来指定一个Activity,并通过startActivity或startActivityForResult方法启动该Activity.以及在Activity之间传递数据：

public class MainActivity extends Activity { private Button btn1,btn2; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); LinearLayout view = new LinearLayout(this); view.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT)); btn1 = new Button(this); btn1.setId(1); btn1.setText("使用类名开启另一个Activity"); btn1.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)); btn2 = new Button(this); btn2.setId(2); btn2.setText("使用action开启另一个Activity"); btn2.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)); view.addView(btn1); view.addView(btn2); setContentView(view); btn1.setOnClickListener(listener); btn2.setOnClickListener(listener); } private View.OnClickListener listener = new OnClickListener() { @Override public void onClick(View view) { Intent intent = new Intent(); switch (view.getId()) { case 1: intent.setClass(MainActivity.this, ResultActivity.class); intent.putExtra("name", "JAVA"); startActivityForResult(intent, 222); break; case 2: intent.setAction("forResult"); MyData myData = new MyData(); //使用putExtra传递自定义对象时，该对象必须实现序列化，该类中的所有成员属性也必须实现序列化接口 intent.putExtra("data", myData); startActivity(intent); break; default: break; } } }; @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { //requestCode是请求码，即startActivityForResult(intent, 222)中的第二个参数 //resultCode是结果码，即setResult(333)中设置的数字 switch (requestCode) { case 222: if(resultCode == 333){ Toast.makeText(this, "无结果返回...", Toast.LENGTH_LONG).show(); } else if(resultCode == 444){ Toast.makeText(this, data.getStringExtra("result"), Toast.LENGTH_LONG).show(); } break; default: break; } } }public class ResultActivity extends Activity { private Button btn1 , btn2; private TextView tv; private Intent intent; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); intent = getIntent(); LinearLayout view = new LinearLayout(this); view.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT)); tv = new TextView(this); tv.setText("name is "+intent.getStringExtra("name")); tv.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)); btn1 = new Button(this); btn1.setId(1); btn1.setText("Back1"); btn1.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)); btn2 = new Button(this); btn2.setId(2); btn2.setText("Back2"); btn2.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)); view.addView(tv); view.addView(btn1); view.addView(btn2); btn1.setOnClickListener(listener); btn2.setOnClickListener(listener); setContentView(view); } private View.OnClickListener listener = new OnClickListener() { @Override public void onClick(View view) { switch (view.getId()) { case 1: setResult(333); break; case 2: intent.putExtra("result", "带结果返回"); setResult(444, intent); break; default: break; } ResultActivity.this.finish(); } }; }public class Result2Activity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); MyData data = (MyData)getIntent().getSerializableExtra("data"); setTitle(data.value); } }public class MyData implements Serializable { public String value = "this is test"; }

2、Intent指定Activity的方式

2.1 直接使用Class

code :

intent.setClass(MainActivity.this, ResultActivity.class);

manifest :

2.2 使用Action

code :

intent.setAction("forResult");

manifest :

forResult">

2.3 使用包名

code :

ComponentName cn = new ComponentName(MainActivity.this, "com.zj.activity.another.ActivityA");

intent.setComponent(cn);

manifest: