用Android Studio实现消息提示Toast的代码，目标如下：1.通过点击三个按钮分别实现Toast的默认方式、自定义方式、带图标方式3种显示方式。2.用图片作为消息提示的图标

以下是用Android Studio实现消息提示Toast的代码，实现了点击三个按钮分别实现Toast的默认方式、自定义方式、带图标方式3种显示方式，并使用了图片作为消息提示的图标。

XML布局文件：

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center">

    <Button
        android:id="@+id/default_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Default Toast"/>

    <Button
        android:id="@+id/custom_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Custom Toast"/>

    <Button
        android:id="@+id/icon_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Icon Toast"/>

</LinearLayout>

Java代码：

public class MainActivity extends AppCompatActivity {

    private Button defaultButton, customButton, iconButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        defaultButton = findViewById(R.id.default_button);
        customButton = findViewById(R.id.custom_button);
        iconButton = findViewById(R.id.icon_button);

        defaultButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "This is a default toast message.", Toast.LENGTH_SHORT).show();
            }
        });

        customButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                LayoutInflater inflater = getLayoutInflater();
                View layout = inflater.inflate(R.layout.custom_toast_layout,
                        (ViewGroup) findViewById(R.id.custom_toast_container));

                TextView text = layout.findViewById(R.id.text);
                text.setText("This is a custom toast message.");

                Toast toast = new Toast(getApplicationContext());
                toast.setGravity(Gravity.CENTER_VERTICAL, 0, 0);
                toast.setDuration(Toast.LENGTH_SHORT);
                toast.setView(layout);
                toast.show();
            }
        });

        iconButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                LayoutInflater inflater = getLayoutInflater();
                View layout = inflater.inflate(R.layout.icon_toast_layout,
                        (ViewGroup) findViewById(R.id.icon_toast_container));

                ImageView image = layout.findViewById(R.id.image);
                image.setImageResource(R.drawable.icon);

                TextView text = layout.findViewById(R.id.text);
                text.setText("This is an icon toast message.");

                Toast toast = new Toast(getApplicationContext());
                toast.setGravity(Gravity.CENTER_VERTICAL, 0, 0);
                toast.setDuration(Toast.LENGTH_SHORT);
                toast.setView(layout);
                toast.show();
            }
        });
    }
}

custom_toast_layout.xml布局文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/custom_toast_container"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/custom_toast_background"
    android:orientation="horizontal"
    android:padding="16dp">

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textColor="#FFFFFF"
        android:textSize="16sp" />

</LinearLayout>

icon_toast_layout.xml布局文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/icon_toast_container"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/icon_toast_background"
    android:orientation="horizontal"
    android:padding="16dp">

    <ImageView
        android:id="@+id/image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginRight="16dp" />

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textColor="#FFFFFF"
        android:textSize="16sp" />

</LinearLayout>

custom_toast_background.xml和icon_toast_background.xml文件分别为自定义Toast的背景，可以根据需要自行设置。