如果是只有一个Activity的App就没有必要写BaseActivity，但一旦大于一个我还是建议写一个BaseActivity，准没错。
每个Activity通常都是绑定视图，绑定控件，监听控件，获取Bundle，跳转Activity还有一些很有些烦人的小功能如：Toast，findViewById，我们都可以封装一层简化他们的使用
BaseActivity的代码如下：
public abstract class BaseActivity extends Activity implements View.OnClickListener { /** 是否沉浸状态栏 **/ private boolean isSetStatusBar = true; /** 是否允许全屏 **/ private boolean mAllowFullScreen = true; /** 是否禁止旋转屏幕 **/ private boolean isAllowScreenRoate = false; /** 当前Activity渲染的视图View **/ private View mContextView = null; /* * 日志输出标志 **/ protected final String TAG = this.getClass().getSimpleName(); /* * View点击 **/ public abstract void widgetClick(View v); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Log.d(TAG, "BaseActivity-->onCreate()"); Bundle bundle = getIntent().getExtras(); initParms(bundle); View mView = bindView(); if (null == mView) { mContextView = LayoutInflater.from(this) .inflate(bindLayout(), null); } else mContextView = mView; if (mAllowFullScreen) { requestWindowFeature(Window.FEATURE_NO_TITLE); } if (isSetStatusBar) { steepStatusBar(); } setContentView(mContextView); if (!isAllowScreenRoate) { setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT); } initView(mContextView); setListener(); doBusiness(this); } /** * [沉浸状态栏] */ private void steepStatusBar() { if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) { // 透明状态栏 getWindow().addFlags( WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS); // 透明导航栏 getWindow().addFlags( WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION); } } /** * [初始化参数] * * @param parms */ public abstract void initParms(Bundle parms); /** * [绑定视图] * * @return */ public abstract View bindView(); /** * [绑定布局] * * @return */ public abstract int bindLayout(); /** * [初始化控件] * * @param view */ public abstract void initView(final View view); /** * [绑定控件] * * @param resId * * @return */ protected <T extends View> T $(int resId) { return (T) super.findViewById(resId); } /** * [设置监听] */ public abstract void setListener(); @Override public void onClick(View v) { widgetClick(v); } /** * [业务操作] * * @param mContext */ public abstract void doBusiness(Context mContext); /** * [页面跳转] * * @param clz */ public void startActivity(Class<?> clz) { startActivity(new Intent(BaseActivity.this,clz)); } /** * [携带数据的页面跳转] * * @param clz * @param bundle */ public void startActivity(Class<?> clz, Bundle bundle) { Intent intent = new Intent(); intent.setClass(this, clz); if (bundle != null) { intent.putExtras(bundle); } startActivity(intent); } /** * [含有Bundle通过Class打开编辑界面] * * @param cls * @param bundle * @param requestCode */ public void startActivityForResult(Class<?> cls, Bundle bundle, int requestCode) { Intent intent = new Intent(); intent.setClass(this, cls); if (bundle != null) { intent.putExtras(bundle); } startActivityForResult(intent, requestCode); } @Override protected void onRestart() { super.onRestart(); Log.d(TAG, "onRestart()");} @Override protected void onStart() { super.onStart(); Log.d(TAG, "onStart()"); } @Override protected void onResume() { super.onResume(); Log.d(TAG, "onResume()"); } @Override protected void onPause() { super.onPause(); Log.d(TAG, "onPause()"); } @Override protected void onStop() { super.onStop(); Log.d(TAG, "onStop()"); } @Override protected void onDestroy() { super.onDestroy(); Log.d(TAG, "onDestroy()"); } /** * [简化Toast] * @param msg */ protected void showToast(String msg){ Toast.makeText(this,msg,Toast.LENGTH_SHORT).show(); } /** * [是否允许屏幕旋转] * * @param isAllowScreenRoate */ public void setScreenRoate(boolean isAllowScreenRoate) { this.isAllowScreenRoate = isAllowScreenRoate; } } /** * [是否允许全屏] * * @param allowFullScreen */ public void setAllowFullScreen(boolean allowFullScreen) { this.mAllowFullScreen = allowFullScreen; } /** * [是否设置沉浸状态栏] * * @param isSetStatusBar */ public void setSteepStatusBar(boolean isSetStatusBar) { this.isSetStatusBar = isSetStatusBar; } /** * [是否允许屏幕旋转] * * @param isAllowScreenRoate */ public void setScreenRoate(boolean isAllowScreenRoate) { this.isAllowScreenRoate = isAllowScreenRoate; } } [是否设置沉浸状态栏] * * @param isSetStatusBar */ public void setSteepStatusBar(boolean isSetStatusBar) { this.isSetStatusBar = isSetStatusBar; } /** * [是否允许屏幕旋转] * *@param isAllowScreenRoate */ public void setScreenRoate(boolean isAllowScreenRoate) { this.isAllowScreenRoate = isAllowScreenRoate; } }
继承自BaseActivity的Activity使用如下：
public class MainActivity extends BaseActivity { private Button btn1; @Override public void widgetClick(View v) { switch (v.getId()){ case R.id.button: //用简化了的toast和startActivity showToast("toast"); startActivity(Main2Activity.class); break;} } @Override public void initParms(Bundle parms) { //解析bundle内容或者设置是否旋转，沉浸，全屏 } @Override public View bindView() { return null; } @Override public int bindLayout(){ return R.layout.activity_main; } @Override public void initView(View view) { btn1=$(R.id.button); } @Override public void setListener() { btn1.setOnClickListener(this); } @Override public void doBusiness(Context mContext) { } }
可以看到还是很多重复代码的，所以说搞一个BaseActivity是多么有必要，而且Fragment也要搞一个基类，方法也类似，这样可以大大减少重复代码，而且管理起来还比较容易，保持了样式的一致，如果想个性化也预留了相应的方法。
