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Diffstat (limited to 'sdk-android-tutorial-a-running-pipeline.md')
| -rw-r--r-- | sdk-android-tutorial-a-running-pipeline.md | 40 |
1 files changed, 20 insertions, 20 deletions
diff --git a/sdk-android-tutorial-a-running-pipeline.md b/sdk-android-tutorial-a-running-pipeline.md index 5545ffa..af9613d 100644 --- a/sdk-android-tutorial-a-running-pipeline.md +++ b/sdk-android-tutorial-a-running-pipeline.md @@ -1,6 +1,6 @@ # Android tutorial 2: A running pipeline -## Goal +### Goal ![screenshot] @@ -20,7 +20,7 @@ learn: - How to allocate a `CustomData` structure from C and have Java host it -## Introduction +### Introduction When using a Graphical User Interface (UI), if the application waits for GStreamer calls to complete the user experience will suffer. The usual @@ -52,7 +52,7 @@ The code below builds a pipeline with an `audiotestsrc` and an setting the pipeline to PLAYING or PAUSED. A TextView in the UI shows messages sent from the C code (for errors and state changes). -## A pipeline on Android \[Java code\] +### A pipeline on Android \[Java code\] **src/org/freedesktop/gstreamer/tutorials/tutorial\_2/Tutorial2.java** @@ -337,7 +337,7 @@ all allocated resources. This concludes the UI part of the tutorial. -## A pipeline on Android \[C code\] +### A pipeline on Android \[C code\] **jni/tutorial-2.c** @@ -356,11 +356,11 @@ GST_DEBUG_CATEGORY_STATIC (debug_category); * a jlong, which is always 64 bits, without warnings. */ #if GLIB_SIZEOF_VOID_P == 8 -# define GET_CUSTOM_DATA(env, thiz, fieldID) (CustomData *)(*env)->GetLongField (env, thiz, fieldID) -# define SET_CUSTOM_DATA(env, thiz, fieldID, data) (*env)->SetLongField (env, thiz, fieldID, (jlong)data) +## define GET_CUSTOM_DATA(env, thiz, fieldID) (CustomData *)(*env)->GetLongField (env, thiz, fieldID) +## define SET_CUSTOM_DATA(env, thiz, fieldID, data) (*env)->SetLongField (env, thiz, fieldID, (jlong)data) #else -# define GET_CUSTOM_DATA(env, thiz, fieldID) (CustomData *)(jint)(*env)->GetLongField (env, thiz, fieldID) -# define SET_CUSTOM_DATA(env, thiz, fieldID, data) (*env)->SetLongField (env, thiz, fieldID, (jlong)(jint)data) +## define GET_CUSTOM_DATA(env, thiz, fieldID) (CustomData *)(jint)(*env)->GetLongField (env, thiz, fieldID) +## define SET_CUSTOM_DATA(env, thiz, fieldID, data) (*env)->SetLongField (env, thiz, fieldID, (jlong)(jint)data) #endif /* Structure to contain all our information, so we can pass it to callbacks */ @@ -712,7 +712,7 @@ done for simplicity). Let’s review now the first native method which can be directly called from Java: -### `gst_native_init()` (`nativeInit()` from Java) +#### `gst_native_init()` (`nativeInit()` from Java) This method is called at the end of Java's `onCreate()`. @@ -741,7 +741,7 @@ pthread_create (&gst_app_thread, NULL, &app_function, data); Finally, a thread is created and it starts running the `app_function()` method. -### `app_function()` +#### `app_function()` ``` c /* Main method for the native code. This is executed on its own thread. */ @@ -820,7 +820,7 @@ reviewed below. Once the main loop has quit, all resources are freed in lines 178 to 181. -### `check_initialization_complete()` +#### `check_initialization_complete()` ``` c static void check_initialization_complete (CustomData *data) { @@ -864,7 +864,7 @@ This behavior is implemented in the `get_jni_env()` method, used for example in `check_initialization_complete()` as we have just seen. Let’s see how it works, step by step: -### `get_jni_env()` +#### `get_jni_env()` ``` c static JNIEnv *get_jni_env (void) { @@ -886,13 +886,13 @@ If it returns NULL, we never attached this thread, so we do now with with [pthread\_setspecific()](http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_setspecific.html). -### `attach_current_thread()` +#### `attach_current_thread()` This method is simply a convenience wrapper around [AttachCurrentThread()](http://docs.oracle.com/javase/1.5.0/docs/guide/jni/spec/invocation.html#attach_current_thread) to deal with its parameters. -### `detach_current_thread()` +#### `detach_current_thread()` This method is called by the pthreads library when a TLS key is deleted, meaning that the thread is about to be destroyed. We simply detach the @@ -901,7 +901,7 @@ thread from the JavaVM with Let's now review the rest of the native methods accessible from Java: -### `gst_native_finalize()` (`nativeFinalize()` from Java) +#### `gst_native_finalize()` (`nativeFinalize()` from Java) ``` c static void gst_native_finalize (JNIEnv* env, jobject thiz) { @@ -936,7 +936,7 @@ about to be destroyed. Here, we: `Tutorial2` class to NULL with `SET_CUSTOM_DATA()`. -### `gst_native_play` and `gst_native_pause()` (`nativePlay` and `nativePause()` from Java) +#### `gst_native_play` and `gst_native_pause()` (`nativePlay` and `nativePause()` from Java) These two simple methods retrieve `CustomData` from the passed-in object with `GET_CUSTOM_DATA()` and set the pipeline found inside `CustomData` @@ -944,13 +944,13 @@ to the desired state, returning immediately. Finally, let’s see how the GStreamer callbacks are handled: -### `error_cb` and `state_changed_cb` +#### `error_cb` and `state_changed_cb` This tutorial does not do much in these callbacks. They simply parse the error or state changed message and display a message in the UI using the `set_ui_message()` method: -### `set_ui_message()` +#### `set_ui_message()` ``` c static void set_ui_message (const gchar *message, CustomData *data) { @@ -993,7 +993,7 @@ We check for exceptions with the JNI method and free the UTF16 message with [DeleteLocalRef()](http://docs.oracle.com/javase/1.5.0/docs/guide/jni/spec/functions.html#DeleteLocalRef). -## A pipeline on Android \[Android.mk\] +### A pipeline on Android \[Android.mk\] **jni/Android.mk** @@ -1028,7 +1028,7 @@ And this is it\! This has been a rather long tutorial, but we covered a lot of territory. Building on top of this one, the following ones are shorter and focus only on the new topics. -## Conclusion +### Conclusion This tutorial has shown: |