Android自定义单例AlertDialog详解

当Android开发处理错误信息时，经常会以Dialog的形式显示错误信息，但是每次都new一个Dialog，很麻烦，也增加程序的开销，所以今天就分享一种自定义单例AlertDialog

public class AlertDialog {  private static AlertDialog alertDialog = null;  private Context context;  private Dialog dialog;  private LinearLayout lLayout_bg;  private TextView txt_title;  private TextView txt_msg;  private Button btn_neg;  private Button btn_pos;  private ImageView img_line;  private Display display;  private boolean showTitle = false;  private boolean showMsg = false;  private boolean showPosBtn = false;  private boolean showNegBtn = false;  public static AlertDialog getInstance(Context context){    if (alertDialog==null){      synchronized (AlertDialog.class) {        if (alertDialog == null) {          alertDialog = new AlertDialog(context).builder();        }      }    }    return alertDialog;  }  public AlertDialog(Context context) {    this.context = context;    WindowManager windowManager = (WindowManager) context        .getSystemService(Context.WINDOW_SERVICE);    display = windowManager.getDefaultDisplay();  }  public AlertDialog builder() {    // 获取Dialog布局    View view = LayoutInflater.from(context).inflate(R.layout.view_alertdialog, null);    // 获取自定义Dialog布局中的控件    lLayout_bg = (LinearLayout) view.findViewById(R.id.lLayout_bg);    txt_title = (TextView) view.findViewById(R.id.txt_title);    txt_title.setVisibility(View.GoNE);    txt_msg = (TextView) view.findViewById(R.id.txt_msg);    txt_msg.setVisibility(View.GONE);    btn_neg = (Button) view.findViewById(R.id.btn_neg);    btn_neg.setVisibility(View.GONE);    btn_pos = (Button) view.findViewById(R.id.btn_pos);    btn_pos.setVisibility(View.GONE);    img_line = (ImageView) view.findViewById(R.id.img_line);    img_line.setVisibility(View.GONE);    // 定义Dialog布局和参数    dialog = new Dialog(context, R.style.AlertDialogStyle);    dialog.setContentView(view);    // 调整dialog背景大小    lLayout_bg.setLayoutParams(new FrameLayout.LayoutParams((int) (display        .getWidth() * 0.85), LayoutParams.WRAP_CONTENT));    return this;  }  public AlertDialog setTitle(String title) {    showTitle = true;    if ("".equals(title)) {      txt_title.setText("标题");    } else {      txt_title.setText(title);    }    return this;  }  public AlertDialog setMsg(String msg) {    showMsg = true;    if ("".equals(msg)) {      txt_msg.setText("内容");    } else {      txt_msg.setText(msg);    }    return this;  }  public AlertDialog setMsg(int rId) {    showMsg = true;    txt_msg.setText(rId);    return this;  }  public AlertDialog setCancelable(boolean cancel) {    dialog.setCancelable(cancel);    return this;  }  public AlertDialog setPositiveButton(String text,      final OnClickListener listener) {    showPosBtn = true;    if ("".equals(text)) {      btn_pos.setText("确定");    } else {      btn_pos.setText(text);    }    btn_pos.setOnClickListener(new OnClickListener() {      @Override      public void onClick(View v) {        if(listener!=null) {          listener.onClick(v);        }        dialog.dismiss();      }    });    return this;  }  public AlertDialog setNegativeButton(String text,      final OnClickListener listener) {    showNegBtn = true;    if ("".equals(text)) {      btn_neg.setText("取消");    } else {      btn_neg.setText(text);    }    btn_neg.setOnClickListener(new OnClickListener() {      @Override      public void onClick(View v) {        if(listener!=null) {          listener.onClick(v);        }        dialog.dismiss();      }    });    return this;  }  private void setLayout() {    if (!showTitle && !showMsg) {      txt_title.setText("");      txt_title.setVisibility(View.VISIBLE);    }    if (showTitle) {      txt_title.setVisibility(View.VISIBLE);    }    if (showMsg) {      txt_msg.setVisibility(View.VISIBLE);    }    if (!showPosBtn && !showNegBtn) {      btn_pos.setText("确定");      btn_pos.setVisibility(View.VISIBLE);      btn_pos.setBackgroundResource(R.drawable.alertdialog_single_selector);      btn_pos.setOnClickListener(new OnClickListener() {        @Override        public void onClick(View v) {          dialog.dismiss();        }      });    }    if (showPosBtn && showNegBtn) {      btn_pos.setVisibility(View.VISIBLE);      btn_pos.setBackgroundResource(R.drawable.alertdialog_right_selector);      btn_neg.setVisibility(View.VISIBLE);      btn_neg.setBackgroundResource(R.drawable.alertdialog_left_selector);      img_line.setVisibility(View.VISIBLE);    }    if (showPosBtn && !showNegBtn) {      btn_pos.setVisibility(View.VISIBLE);      btn_pos.setBackgroundResource(R.drawable.alertdialog_single_selector);    }    if (!showPosBtn && showNegBtn) {      btn_neg.setVisibility(View.VISIBLE);      btn_neg.setBackgroundResource(R.drawable.alertdialog_single_selector);    }  }  public void show() {    setLayout();    dialog.show();  }}