android界面返回键与弹框的编写

public class BaseActivity extends AppCompatActivity {

    //让返回键起作用
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        Log.i("info","执行BaseActivity中的onOptionsItemSelected");

        if (android.R.id.home == item.getItemId()) {
            this.finish();          //关闭当前接口
            return true;
        }

        return super.onOptionsItemSelected(item);
    }


    public void getActionBar(String title, AppCompatActivity activity) {
        // 设置标题栏返回键
        ActionBar callbackBar = activity.getSupportActionBar();

        if (callbackBar != null) {
            callbackBar.setDisplayHomeAsUpEnabled(true);//给左上角添加一个返回的箭头图标
            callbackBar.setHomeButtonEnabled(true);//设置图标可以点击
            callbackBar.setDisplayShowHomeEnabled(true);//使图标可以显示
            callbackBar.setTitle(title); //标题设置
        }
    }


    protected void showMessage(String message) {
        String title = Constant.appName;
        String negativeBtnText = Constant.btnTextOK;
        // 绑定失败，提示后退出应用
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(this);
        alertDialog.setTitle(title);
        alertDialog.setMessage(message);
        alertDialog.setNegativeButton(negativeBtnText, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.cancel();
            }
        });
        alertDialog.setCancelable(false);
        alertDialog.show();
    }

}

//继承BaseActivity直接调用方法。

public class IDCardOperationActivity extends BaseActivity implements View.OnClickListener {


    yhid15reader yhidReader = new yhid15reader();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        //创建静态内部类
        super.onCreate(savedInstanceState);
     
        //当前窗口设置返回按键
        getActionBar("身份证模块", this);

    }

    //调用消息弹框。
    public void show(View v) {
            showMessage("Open 成功");
  
    }

}