在红皮书第七章(p127)Using Intents and the Phone Dialer中

有个程序是用intent打开Dialer这个application其中有几行代码是这样写的

Intent DialIntent = new Intent(Intent.DIAL_ACTION,Uri.parse("tel:5551212"));DialIntent.setLaunchFlags(Intent.NEW_TASK_LAUNCH );

其中第一行中的Intent.DIAL_ACTION在eclipse中出现错误(Intent.DIAL_ACTION can not be resolved)，

需要将其改为Intent.ACTION_DIAL.

第二行代码中的Intent.NEW_TASK_LAUNCH也有错误(Intent.NEW_TASK_LAUNCH can not be resolved)

需要将其改为 DialIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

关于Uri.parse(String uristring)方法

public static Uri  parse(String uriString)

Creates a Uri which parses the given encoded URI string.

Parameters

uriString     an RFC 3296-compliant, encoded URI

Returns

* Uri for this given uri string

Throws

NullPointerException     if uriString is null

这个方法是将uristring转化为Uri形式，并返回Uri形式的引用。如果Uristring为null将产生异常。

在android文档中，没有setLaunchFlags(int flags)这个方法，但却有setFlags(int flags)方法。

通过查android文档我们可以看到setfFlags(int flags)方法的定义如下：

public Intent setFlags(int flags)

Set special flags controlling how this intent is handled. Most values here depend on the type of component being executed by the Intent,

specifically the FLAG_ACTIVITY_* flags are all for use with Context.startActivity() and the FLAG_RECEIVER_* flags are all for use

with Context.sendBroadcast().

See the Application Model documentation for important information on how some of these options impact the behavior of your application.

Parameters

flags     The desired flags.

Returns

* Returns the same Intent object, for chaining multiple calls into a single statement.

See Also

* getFlags()* addFlags(int)* FLAG_GRANT_READ_URI_PERMISSION* FLAG_GRANT_WRITE_URI_PERMISSION* FLAG_DEBUG_LOG_RESOLUTION* FLAG_FROM_BACKGROUND* FLAG_ACTIVITY_RESET_TASK_IF_NEEDED* FLAG_ACTIVITY_BROUGHT_TO_FRONT* FLAG_ACTIVITY_CLEAR_TOP* FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS* FLAG_ACTIVITY_FORWARD_RESULT* FLAG_ACTIVITY_MULTIPLE_TASK* FLAG_ACTIVITY_NEW_TASK* FLAG_ACTIVITY_NO_HISTORY* FLAG_ACTIVITY_SINGLE_TOP* FLAG_RECEIVER_REGISTERED_ONLY

可以看出在以上的flags常量中没有NEW_TASK_LAUNCH.

public static final int FLAG_ACTIVITY_NEW_TASK

If set, this activity will become the start of a new task on this history stack.

A task (from the activity that started it to the next task activity) defines an

atomic group of activities that the user can move to. Tasks can be moved to the

foreground and background; all of the activities inside of a particular task

always remain in the same order. See the Application Model documentation for

more details on tasks.

This flag is generally used by activities that want to present a "launcher" style

behavior: they give the user a list of separate things that can be done, which

otherwise run completely independently of the activity launching them.

When using this flag, if a task is already running for the activity you are now

starting, then a new activity will not be started; instead, the current task will

simply be brought to the front of the screen with the state it was last in. See

FLAG_ACTIVITY_MULTIPLE_TASK for a flag to disable this behavior.

This flag can not be used when the caller is requesting a result from the activity being launched.

Constant Value: 268435456 (0x10000000)

最终代码：

package com.android.AndroidPhoneDalier;

import android.app.Activity;

import android.os.Bundle;

import  android.content.Intent;

import android.net.Uri;

public class AndroidPhoneDalier extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

Intent DialIntent = new Intent(Intent.ACTION_DIAL,Uri.parse("tel:88161644"));

DialIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

startActivity(DialIntent);

}

}

各种FlAG定义

public static final int FLAG_ACTIVITY_BROUGHT_TO_FRONT

This flag is not normally set by application code, but set for

you by the system as described in the launchMode documentation for the singleTask mode.

Constant Value: 4194304 (0x00400000)

public static final int FLAG_ACTIVITY_CLEAR_TOP

If set, and the activity being launched is already running in

the current task, then instead of launching a new instance of

that activity, all of the other activities on top of it will

be closed and this Intent will be delivered to the (now on top)

old activity as a new Intent.

For example, consider a task consisting of the activities: A, B, C, D. If D calls

startActivity() with an Intent that resolves to the component of activity B,

then C and D will be finished and B receive the given Intent, resulting in the stack now being: A, B.

The currently running instance of task B in the above example will either

receiving the new intent you are starting here in its onNewIntent() method,

or be itself finished and restarting with the new intent. If it has declared

its launch mode to be "multiple" (the default) it will be finished and

re-created; for all other launch modes it will receive the Intent in the current instance.

This launch mode can also be used to good effect in conjunction

with FLAG_ACTIVITY_NEW_TASK: if used to start the root activity of a task,

it will bring any currently running instance of that task to the foreground,

and then clear it to its root state. This is especially useful, for example,

when launching an activity from the notification manager.

See the Application Model documentation for more details on tasks.

Constant Value: 67108864 (0x04000000)

public static final int FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS

If set, the new activity is not kept in the list of recently

launched activities.

Constant Value: 8388608 (0x00800000)

public static final int FLAG_ACTIVITY_FORWARD_RESULT

If set and this intent is being used to launch a new activity

from an existing one, then the reply target of the existing

activity will be transfered to the new activity. This way the

new activity can call setResult(int) and have that result sent

back to the reply target of the original activity.

Constant Value: 33554432 (0x02000000)

public static final int FLAG_ACTIVITY_LAUNCHED_FROM_HISTORY

If set, this activity is being launched from history (longpress home key).

Constant Value: 1048576 (0x00100000)

public static final int FLAG_ACTIVITY_MULTIPLE_TASK

Do not use this flag unless you are implementing your own top-level

application launcher. Used in conjunction with FLAG_ACTIVITY_NEW_TASK

to disable the behavior of bringing an existing task to the foreground.

When set, a new task is always started to host the Activity for the Intent,

regardless of whether there is already an existing task running the same thing.

Because the default system does not include graphical task management,

you should not use this flag unless you provide some way for a user to

return back to the tasks you have launched.

This flag is ignored if FLAG_ACTIVITY_NEW_TASK is not set.

See the Application Model documentation for more details on tasks.

Constant Value: 134217728 (0x08000000)

public static final int FLAG_ACTIVITY_NEW_TASK

If set, this activity will become the start of a new

task on this history stack. A task (from the activity that

started it to the next task activity) defines an atomic group

of activities that the user can move to. Tasks can be moved to

the foreground and background; all of the activities inside of a

particular task always remain in the same order. See the Application

Model documentation for more details on tasks.

This flag is generally used by activities that want to present

a "launcher" style behavior: they give the user a list of separate

things that can be done, which otherwise run completely independently

of the activity launching them.

When using this flag, if a task is already running for the activity you

are now starting, then a new activity will not be started; instead, the

current task will simply be brought to the front of the screen with the

state it was last in. See FLAG_ACTIVITY_MULTIPLE_TASK for a flag to disable this behavior.

This flag can not be used when the caller is requesting a result from the activity being launched.

Constant Value: 268435456 (0x10000000)

public static final int FLAG_ACTIVITY_NO_HISTORY

If set, the new activity is not kept in the history stack.

Constant Value: 1073741824 (0x40000000)

public static final int FLAG_ACTIVITY_PREVIOUS_IS_TOP

If set and this intent is being used to launch a new activity

from an existing one, the current activity will not be counted

as the top activity for deciding whether the new intent should be

delivered to the top instead of starting a new one. The previous

activity will be used as the top, with the assumption being that

the current activity will finish itself immediately.

Constant Value: 16777216 (0x01000000)

public static final int FLAG_ACTIVITY_RESET_TASK_IF_NEEDED

If set, and this activity is either being started in a new task or

bringing to the top an existing task, then it will be launched as

the front door of the task. This will result in the application of

any affinities needed to have that task in the proper state

(either moving activities to or from it), or simply resetting that

task to its initial state if needed.

Constant Value: 2097152 (0x00200000)

public static final int FLAG_ACTIVITY_SINGLE_TOP

If set, the activity will not be launched if it is

already running at the top of the history stack.

Constant Value: 536870912 (0x20000000)

public static final int FLAG_DEBUG_LOG_RESOLUTION

A flag you can enable for debugging: when set, log messages

will be printed during the resolution of this intent to show

you what has been found to create the final resolved list.

Constant Value: 8 (0x00000008)

public static final int FLAG_FROM_BACKGROUND

Can be set by the caller to indicate that this Intent is

coming from a background operation, not from direct user interaction.

Constant Value: 4 (0x00000004)

public static final int FLAG_GRANT_READ_URI_PERMISSION

If set, the recipient of this Intent will be granted permission

to perform read operations on the Uri in the Intent's data.

Constant Value: 1 (0x00000001)

public static final int FLAG_GRANT_WRITE_URI_PERMISSION

If set, the recipient of this Intent will be granted permission

to perform write operations on the Uri in the Intent's data.

Constant Value: 2 (0x00000002)

public static final int FLAG_RECEIVER_REGISTERED_ONLY

If set, when sending a broadcast only registered receivers will be

called -- no BroadcastReceiver components will be launched.

Constant Value: 1073741824 (0x40000000)