Android应用程序四大组件之Activity入门（Demo）

package com.android.helloactivitybasic; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.Toast; /** * (c) 2011 SZJ * * @author SZJ * @since 2011-12-8 - 下午3:51:44 * @description Activity A */ public class HelloActivityBasicActivity extends Activity { // =========================================================== // Constants // =========================================================== private static final int GET_MESSAGE_REQUEST = 0; private static final String DEBUG_TAG = "View Activity Life Cycles"; // =========================================================== // Fields // =========================================================== private Button mButtonFinish; private Button mButtonStartAnotherActivity; private Button mButtonStartAnotherActivityForResult; // =========================================================== // Constructors // =========================================================== // =========================================================== // Getter & Setter // =========================================================== // =========================================================== // Methods for/from SuperClass/Interfaces // =========================================================== /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); findViews(); setEventHandlers(); Log.d(DEBUG_TAG, "Activity A onCreate()"); } @Override protected void onRestart() { // TODO Auto-generated method stub super.onRestart(); Log.d(DEBUG_TAG, "Activity A onRestart()"); } @Override protected void onStart() { // TODO Auto-generated method stub super.onStart(); Log.d(DEBUG_TAG, "Activity A onStart()"); } @Override protected void onResume() { // TODO Auto-generated method stub super.onResume(); Log.d(DEBUG_TAG, "Activity A onResume()"); } @Override protected void onPause() { // TODO Auto-generated method stub super.onPause(); Log.d(DEBUG_TAG, "Activity A onPause()"); } @Override protected void onStop() { // TODO Auto-generated method stub super.onStop(); Log.d(DEBUG_TAG, "Activity A onStop()"); } @Override protected void onDestroy() { // TODO Auto-generated method stub super.onDestroy(); Log.d(DEBUG_TAG, "Activity A onDestroy()"); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { // TODO Auto-generated method stub if(resultCode == RESULT_OK && requestCode == GET_MESSAGE_REQUEST) { String message = data.getExtras().getString("return_message"); Toast.makeText(HelloActivityBasicActivity.this, message, Toast.LENGTH_LONG).show(); } } // =========================================================== // Methods // =========================================================== private void findViews() { this.mButtonFinish = (Button) findViewById(R.id.button_finish); this.mButtonStartAnotherActivity = (Button) findViewById(R.id.button_start_another_activity); this.mButtonStartAnotherActivityForResult = (Button) findViewById(R.id.button_start_another_activity_for_result); } private void setEventHandlers() { this.mButtonFinish.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub HelloActivityBasicActivity.this.finish(); } }); this.mButtonStartAnotherActivity.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub Intent intent = new Intent(HelloActivityBasicActivity.this, ActivityToBeActivated.class); startActivity(intent); } }); this.mButtonStartAnotherActivityForResult.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub Intent intent = new Intent(HelloActivityBasicActivity.this, ActivityForReturnMessage.class); intent.putExtra("send_message", "Hello, I'm Activity A!"); startActivityForResult(intent, GET_MESSAGE_REQUEST); } }); } // =========================================================== // Inner and Anonymous Classes // =========================================================== }