Toast toast = Toast.makeText(this, "Custom toast creation", Toast.LENGTH_SHORT);
    toast.setGravity(Gravity.BOTTOM | Gravity.RIGHT,0,0);
    toast.show();

从文档中可以看到:

警告:从Android Build开始。VERSION_CODES#R，用于针对API级别构建的应用程序。如果VERSION_CODES#R或更高，则此方法(setGravity)在文本toast上调用时是一个无操作。

这意味着setGravity不能再在API 30+中使用，必须找到另一个来实现所需的行为。

 Toast toast = Toast.makeText(test.this,"bbb", Toast.LENGTH_LONG);

 toast.setGravity(Gravity.CENTER, 0, 0);

 toast.show();

//这是对抗任何错误的最佳解决方案

从文档来看，

Positioning your Toast A standard toast notification appears near the bottom of the screen, centered horizontally. You can change this position with the setGravity(int, int, int) method. This accepts three parameters: a Gravity constant, an x-position offset, and a y-position offset. For example, if you decide that the toast should appear in the top-left corner, you can set the gravity like this: toast.setGravity(Gravity.TOP|Gravity.LEFT, 0, 0); If you want to nudge the position to the right, increase the value of the second parameter. To nudge it down, increase the value of the last parameter.

//一个自定义toast类，可以显示自定义或默认toast)

public class ToastMessage {
            private Context context;
            private static ToastMessage instance;

            /**
             * @param context
             */
            private ToastMessage(Context context) {
                this.context = context;
            }

            /**
             * @param context
             * @return
             */
            public synchronized static ToastMessage getInstance(Context context) {
                if (instance == null) {
                    instance = new ToastMessage(context);
                }
                return instance;
            }

            /**
             * @param message
             */
            public void showLongMessage(String message) {
                Toast.makeText(context, message, Toast.LENGTH_SHORT).show();
            }

            /**
             * @param message
             */
            public void showSmallMessage(String message) {
                Toast.makeText(context, message, Toast.LENGTH_LONG).show();
            }

            /**
             * The Toast displayed via this method will display it for short period of time
             *
             * @param message
             */
            public void showLongCustomToast(String message) {
                LayoutInflater inflater = ((Activity) context).getLayoutInflater();
                View layout = inflater.inflate(R.layout.layout_custom_toast, (ViewGroup) ((Activity) context).findViewById(R.id.ll_toast));
                TextView msgTv = (TextView) layout.findViewById(R.id.tv_msg);
                msgTv.setText(message);
                Toast toast = new Toast(context);
                toast.setGravity(Gravity.FILL_HORIZONTAL | Gravity.BOTTOM, 0, 0);
                toast.setDuration(Toast.LENGTH_LONG);
                toast.setView(layout);
                toast.show();


            }

            /**
             * The toast displayed by this class will display it for long period of time
             *
             * @param message
             */
            public void showSmallCustomToast(String message) {

                LayoutInflater inflater = ((Activity) context).getLayoutInflater();
                View layout = inflater.inflate(R.layout.layout_custom_toast, (ViewGroup) ((Activity) context).findViewById(R.id.ll_toast));
                TextView msgTv = (TextView) layout.findViewById(R.id.tv_msg);
                msgTv.setText(message);
                Toast toast = new Toast(context);
                toast.setGravity(Gravity.FILL_HORIZONTAL | Gravity.BOTTOM, 0, 0);
                toast.setDuration(Toast.LENGTH_SHORT);
                toast.setView(layout);
                toast.show();
            }

        }

如果你得到一个指示你必须调用makeText的错误，下面的代码将修复它:

Toast toast= Toast.makeText(getApplicationContext(), 
"Your string here", Toast.LENGTH_SHORT);  
toast.setGravity(Gravity.TOP|Gravity.CENTER_HORIZONTAL, 0, 0);
toast.show();