深入浅出Google Android BMI计算源代码（Android2.2）

package com.demo.android.bmi; import java.text.DecimalFormat; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.content.Intent; import android.content.SharedPreferences; import android.net.Uri; import android.os.Bundle; import android.util.Log; import android.view.Menu; import android.view.MenuItem; import android.view.SubMenu; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast; public class Bmi extends Activity { private static final String TAG = "Bmi"; private static final String PREF = "BMI_PREF"; private static final String PREF_HEIGHT = "BMI_HEIGHT"; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); findViews(); restorePrefers(); setListeners(); } @Override protected void onStart() { super.onStart(); Log.d(TAG, "onStart"); } @Override protected void onStop() { super.onStop(); Log.d(TAG, "onStop"); SharedPreferences settings = getSharedPreferences(PREF, 0); settings.edit().putString(PREF_HEIGHT, field_height.getText().toString()).commit(); } @Override public void onDestroy() { super.onDestroy(); Log.d(TAG, "onDestroy"); } private Button button_calc; private EditText field_height; private EditText field_weight; private TextView view_result; private TextView view_advice; private void findViews() { button_calc = (Button)findViewById(R.id.submit); field_height = (EditText)findViewById(R.id.height); field_weight = (EditText)findViewById(R.id.weight); view_result = (TextView)findViewById(R.id.result); view_advice = (TextView)findViewById(R.id.advice); } private void setListeners() { button_calc.setOnClickListener(calcBMI); } private Button.OnClickListener calcBMI = new OnClickListener() { public void onClick(View arg0) { try{ Double.parseDouble(field_height.getText().toString()); Double.parseDouble(field_weight.getText().toString()); Intent intent = new Intent(); intent.setClass(Bmi.this, Report.class); Bundle bundle = new Bundle(); bundle.putString("KEY_HEIGHT", field_height.getText().toString()); bundle.putString("KEY_WEIGHT", field_weight.getText().toString()); intent.putExtras(bundle); startActivity(intent); } catch(Exception err) { Log.e(TAG, err.toString()); Toast.makeText(Bmi.this, R.string.input_err, Toast.LENGTH_SHORT).show(); } } }; private void openOptionsDialog() { new AlertDialog.Builder(this) .setTitle(R.string.about_title) .setMessage(R.string.about_msg) .setPositiveButton(R.string.ok_label, new DialogInterface.OnClickListener() { public void onClick(DialogInterface arg0, int arg1) { // TODO Auto-generated method stub } }) .setNegativeButton(R.string.homepage_label, new DialogInterface.OnClickListener() { public void onClick(DialogInterface arg0, int arg1) { // TODO Auto-generated method stub Uri uri = Uri.parse(getString(R.string.homepage_uri)); Intent intent = new Intent(Intent.ACTION_VIEW, uri); startActivity(intent); } }) .show(); } protected static final int MENU_ABOUT = Menu.FIRST; protected static final int MENU_QUIT = Menu.FIRST+1; protected static final int MUNU_FILE = Menu.FIRST+2; @Override public boolean onCreateOptionsMenu(Menu menu) { super.onCreateOptionsMenu(menu); SubMenu fileMenu = menu.addSubMenu(0, MUNU_FILE, 0, "文件"); fileMenu.add(0, MENU_QUIT, 0, "退出"); menu.add(0, MENU_ABOUT, 0, "关于..."); return true; } public boolean onOptionsItemSelected(MenuItem item) { super.onOptionsItemSelected(item); switch(item.getItemId()) { case MENU_ABOUT: openOptionsDialog(); break; case MENU_QUIT: finish(); break; } return true; } private void restorePrefers() { SharedPreferences settings = getSharedPreferences(PREF, 0); String pref_height = settings.getString(PREF_HEIGHT, ""); if(! "".equals(pref_height)) { field_height.setText(pref_height); field_weight.requestFocus(); } } }