用户不能自定义吐司的持续时间。因为NotificationManagerService的scheduleTimeoutLocked()函数没有使用字段duration。源代码如下。

private void scheduleTimeoutLocked(ToastRecord r, boolean immediate)
    {
        Message m = Message.obtain(mHandler, MESSAGE_TIMEOUT, r);
        long delay = immediate ? 0 : (r.duration == Toast.LENGTH_LONG ? LONG_DELAY : SHORT_DELAY);
        mHandler.removeCallbacksAndMessages(r);
        mHandler.sendMessageDelayed(m, delay);
    }

使用Crouton，这是一个非常灵活的吐司库。

油煎面包块

你可以像烤面包一样使用它:

Crouton.makeText(context, "YOUR_MESSAGE", Style.INFO);

或者你甚至可以更深入一点，自定义更多，比如将时间设置为无限!例如，在这里我想显示一个toast消息，直到用户通过点击它来确认它。

private static void showMessage(final Activity context, MessageType type, String header, String message) {
    View v = context.getLayoutInflater().inflate(R.layout.toast_layout, null);
    TextView headerTv = (TextView) v.findViewById(R.id.toastHeader);
    headerTv.setText(header);
    TextView messageTv = (TextView) v.findViewById(R.id.toastMessage);
    messageTv.setText(message);
    ImageView toastIcon = (ImageView) v.findViewById(R.id.toastIcon);

    final Crouton crouton = getCrouton(context, v);
    v.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Crouton.hide(crouton);
        }
    });

    crouton.show();
}

private static Crouton getCrouton(final Activity context, View v) {
    Crouton crouton = Crouton.make(context, v);
    crouton.setConfiguration(new Configuration.Builder().setDuration(Configuration.DURATION_INFINITE).build());
    return crouton;
}

自定义布局，将膨胀为吐司。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:animateLayoutChanges="true"
    android:background="@drawable/shadow_container"
    android:gravity="center_vertical"
    android:orientation="horizontal"
    android:padding="@dimen/default_margin"
    tools:ignore="Overdraw">

    <ImageView
        android:id="@+id/toastIcon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/default_spacing_full"
        android:layout_weight="1"
        android:orientation="vertical">

        <TextView
            android:id="@+id/toastHeader"
            style="@style/ItemText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

        <TextView
            android:id="@+id/toastMessage"
            style="@style/ItemSubText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

    </LinearLayout>

</LinearLayout>

LONG_DELAY吐司显示为3.5秒，SHORT_DELAY吐司显示为2秒。

Toast内部使用INotificationManager并在每次调用Toast.show()时调用它的enqueueToast方法。

使用SHORT_DELAY调用show()两次将再次将同一toast排队。它将显示4秒(2秒+ 2秒)。

类似地，两次使用LONG_DELAY调用show()将再次将同一toast排队。它将显示7秒(3.5秒+ 3.5秒)

我已经开发了一个自定义吐司类，您可以显示吐司所需的持续时间(以毫秒计)

import android.content.Context;
import android.os.Build;
import android.os.Handler;
import android.util.Log;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.WindowManager;
import android.widget.TextView;

public final class ToastHelper {

    private static final String TAG = ToastHelper.class.getName();

    public static interface OnShowListener {
        public void onShow(ToastHelper toast);
    }

    public static interface OnDismissListener {
        public void onDismiss(ToastHelper toast);
    }

    private static final int WIDTH_PADDING_IN_DIP = 25;
    private static final int HEIGHT_PADDING_IN_DIP = 15;
    private static final long DEFAULT_DURATION_MILLIS = 2000L;

    private final Context context;
    private final WindowManager windowManager;
    private View toastView;

    private int gravity = Gravity.CENTER_HORIZONTAL | Gravity.BOTTOM;
    private int mX;
    private int mY;
    private long duration = DEFAULT_DURATION_MILLIS;
    private CharSequence text = "";
    private int horizontalMargin;
    private int verticalMargin;
    private WindowManager.LayoutParams params;
    private Handler handler;
    private boolean isShowing;
    private boolean leadingInfinite;

    private OnShowListener onShowListener;
    private OnDismissListener onDismissListener;

    private final Runnable timer = new Runnable() {

        @Override
        public void run() {
            cancel();
        }
    };

    public ToastHelper(Context context) {
        Context mContext = context.getApplicationContext();
        if (mContext == null) {
            mContext = context;
        }
        this.context = mContext;
        windowManager = (WindowManager) mContext
                .getSystemService(Context.WINDOW_SERVICE);
        init();
    }

    private void init() {
        mY = context.getResources().getDisplayMetrics().widthPixels / 5;
        params = new WindowManager.LayoutParams();
        params.height = WindowManager.LayoutParams.WRAP_CONTENT;
        params.width = WindowManager.LayoutParams.WRAP_CONTENT;
        params.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
                | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON;
        params.format = android.graphics.PixelFormat.TRANSLUCENT;
        params.type = WindowManager.LayoutParams.TYPE_TOAST;
        params.setTitle("ToastHelper");
        params.alpha = 1.0f;
        // params.buttonBrightness = 1.0f;
        params.packageName = context.getPackageName();
        params.windowAnimations = android.R.style.Animation_Toast;
    }

    @SuppressWarnings("deprecation")
    @android.annotation.TargetApi(Build.VERSION_CODES.JELLY_BEAN)
    private View getDefaultToastView() {
        TextView textView = new TextView(context);
        textView.setText(text);
        textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.START);
        textView.setClickable(false);
        textView.setFocusable(false);
        textView.setFocusableInTouchMode(false);
        textView.setTextColor(android.graphics.Color.WHITE);
        // textView.setBackgroundColor(Color.BLACK);
        android.graphics.drawable.Drawable drawable = context.getResources()
                .getDrawable(android.R.drawable.toast_frame);
        if (Build.VERSION.SDK_INT < 16) {
            textView.setBackgroundDrawable(drawable);
        } else {
            textView.setBackground(drawable);
        }
        int wP = getPixFromDip(context, WIDTH_PADDING_IN_DIP);
        int hP = getPixFromDip(context, HEIGHT_PADDING_IN_DIP);
        textView.setPadding(wP, hP, wP, hP);
        return textView;
    }

    private static int getPixFromDip(Context context, int dip) {
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
                dip, context.getResources().getDisplayMetrics());
    }

    public void cancel() {
        removeView(true);
    }

    private void removeView(boolean invokeListener) {
        if (toastView != null && toastView.getParent() != null) {
            try {
                Log.i(TAG, "Cancelling Toast...");
                windowManager.removeView(toastView);
                handler.removeCallbacks(timer);
            } finally {
                isShowing = false;
                if (onDismissListener != null && invokeListener) {
                    onDismissListener.onDismiss(this);
                }
            }
        }
    }

    public void show() {
        if (leadingInfinite) {
            throw new InfiniteLoopException(
                    "Calling show() in OnShowListener leads to infinite loop.");
        }
        cancel();
        if (onShowListener != null) {
            leadingInfinite = true;
            onShowListener.onShow(this);
            leadingInfinite = false;
        }
        if (toastView == null) {
            toastView = getDefaultToastView();
        }
        params.gravity = android.support.v4.view.GravityCompat
                .getAbsoluteGravity(gravity, android.support.v4.view.ViewCompat
                        .getLayoutDirection(toastView));
        if ((gravity & Gravity.HORIZONTAL_GRAVITY_MASK) == Gravity.FILL_HORIZONTAL) {
            params.horizontalWeight = 1.0f;
        }
        if ((gravity & Gravity.VERTICAL_GRAVITY_MASK) == Gravity.FILL_VERTICAL) {
            params.verticalWeight = 1.0f;
        }
        params.x = mX;
        params.y = mY;
        params.verticalMargin = verticalMargin;
        params.horizontalMargin = horizontalMargin;

        removeView(false);
        windowManager.addView(toastView, params);
        isShowing = true;
        if (handler == null) {
            handler = new Handler();
        }
        handler.postDelayed(timer, duration);
    }

    public boolean isShowing() {
        return isShowing;
    }

    public void setDuration(long durationMillis) {
        this.duration = durationMillis;
    }

    public void setView(View view) {
        removeView(false);
        toastView = view;
    }

    public void setText(CharSequence text) {
        this.text = text;
    }

    public void setText(int resId) {
        text = context.getString(resId);
    }

    public void setGravity(int gravity, int xOffset, int yOffset) {
        this.gravity = gravity;
        mX = xOffset;
        mY = yOffset;
    }

    public void setMargin(int horizontalMargin, int verticalMargin) {
        this.horizontalMargin = horizontalMargin;
        this.verticalMargin = verticalMargin;
    }

    public long getDuration() {
        return duration;
    }

    public int getGravity() {
        return gravity;
    }

    public int getHorizontalMargin() {
        return horizontalMargin;
    }

    public int getVerticalMargin() {
        return verticalMargin;
    }

    public int getXOffset() {
        return mX;
    }

    public int getYOffset() {
        return mY;
    }

    public View getView() {
        return toastView;
    }

    public void setOnShowListener(OnShowListener onShowListener) {
        this.onShowListener = onShowListener;
    }

    public void setOnDismissListener(OnDismissListener onDismissListener) {
        this.onDismissListener = onDismissListener;
    }

    public static ToastHelper makeText(Context context, CharSequence text,
            long durationMillis) {
        ToastHelper helper = new ToastHelper(context);
        helper.setText(text);
        helper.setDuration(durationMillis);
        return helper;
    }

    public static ToastHelper makeText(Context context, int resId,
            long durationMillis) {
        String string = context.getString(resId);
        return makeText(context, string, durationMillis);
    }

    public static ToastHelper makeText(Context context, CharSequence text) {
        return makeText(context, text, DEFAULT_DURATION_MILLIS);
    }

    public static ToastHelper makeText(Context context, int resId) {
        return makeText(context, resId, DEFAULT_DURATION_MILLIS);
    }

    public static void showToast(Context context, CharSequence text) {
        makeText(context, text, DEFAULT_DURATION_MILLIS).show();
    }

    public static void showToast(Context context, int resId) {
        makeText(context, resId, DEFAULT_DURATION_MILLIS).show();
    }

    private static class InfiniteLoopException extends RuntimeException {
        private static final long serialVersionUID = 6176352792639864360L;

        private InfiniteLoopException(String msg) {
            super(msg);
        }
    }
}

val toast = Toast.makeText(this, "", Toast.LENGTH_LONG)

val countDownTimer = object : CountDownTimer(5000, 1000) {
    override fun onTick(millisUntilFinished: Long) { }
    override fun onFinish() { toast.cancel() }
}

toast.show()
countDownTimer.start()

你可能想试试:

for (int i=0; i < 2; i++)
{
      Toast.makeText(this, "blah", Toast.LENGTH_LONG).show();
}

使时间加倍。如果你指定3而不是2，它会使时间增加三倍等等。